2.1Choosing & installing a theme
The essentials in 30 seconds
- The theme defines the entire appearance of the site: layout, colours, typography, header and footer.
- Block themes (FSE) are customised in the site editor; classic themes through the Customiser.
- Install only from the official directory or a reputable developer: pirated themes hide malware.
Running mini-case — choosing the workshop's look
Samir has to dress Hassan's site: a warm, understated atmosphere that showcases the ceramics. He browses the official directory and hesitates between a theme packed with animations and a light block theme. He knows that a heavy theme will slow the site down and complicate changes. This section gives him objective criteria for choosing.
Sequel to case 1.5 — the settings are in place, now for the appearance.
1. The role of the theme
The theme is the complete look of the site: it decides the layout, colours, fonts, header and footer. Changing theme instantly changes the whole appearance without touching the content. WordPress offers thousands of free and paid themes, but they are not all equal.
A distinction is made between classic themes, customised through the Customiser, and block themes (FSE-compatible), which are edited entirely with Gutenberg blocks. Block themes represent the modern direction of WordPress and offer great flexibility without code.
2. The criteria for a good theme
A good theme is light and fast: it does not load dozens of unnecessary scripts. It is regularly updated, well rated and compatible with the version of WordPress in use. Avoid bloated all-in-one themes that promise everything and slow the site down, as well as pirated themes, which often carry malware.
Samir therefore installs from the official directory (wordpress.org/themes) and favours an understated block theme, such as a recent Twenty theme or a well-known light theme. He uses the preview before activation and checks the rendering on mobile.
🔎 Concrete example — Choosing for the workshop (Samir's case)
Needs: warm atmosphere, photos showcased, fast site.
Ruled out: pirated "premium" theme, heavy on animations and not updated.
Ruled out: theme packed with unnecessary modules.
Selected: light block theme, rated, recently updated, FSE-compatible.
→ Preview, then activate.Result: a healthy, fast and editable foundation.
Lesson: you choose on criteria, not on a marketing promise.
Section vocabulary
- Theme
- The complete look of the site: layout, colours, fonts, header and footer.
Simple example: the theme gives the workshop its warm atmosphere.
What it is not: confusing the theme with a feature plugin.
Reflex: appearance = theme.
- Classic theme / block theme
- Classic: customised through the Customiser; block (FSE): edited entirely with Gutenberg.
Simple example: Samir chooses a block theme so he can change the header without code.
What it is not: believing a block theme prevents you from using plugins.
Reflex: blocks = the modern direction.
- Official directory
- The safe source of verified, free themes that can be installed from the dashboard.
Simple example: Samir installs from wordpress.org/themes.
What it is not: downloading a "nulled" theme from a forum.
Reflex: official = verified.
- Child theme
- A theme that inherits from a parent theme and allows changes that survive updates.
Simple example: used later to customise the style (section 4.4).
What it is not: editing the parent theme directly.
Reflex: lasting customisation = child theme.
- Good theme
- Light, fast, updated, well rated, block-compatible and without unnecessary bloat.
Simple example: an understated theme that lets the photos speak.
What it is not: choosing a theme based on the number of spectacular demos.
Reflex: restraint = performance and maintenance.
In practice — Choosing and installing a quality theme
- Appearance → Themes → Add New: filter by popularity and ratings.
- Check the last update date, the rating and compatibility.
- Install the theme, then use the preview before activation.
- Activate it and check the rendering on desktop and mobile.
Ready-to-say script — justifying the theme choice (25 s)
"I'm choosing a light, recent theme that showcases your photos without slowing the site down. We avoid themes overloaded with animations: they look good in a demo but are slow day to day, and harder to maintain."
Link the choice to speed and to the lifespan of the site.
Copy-paste template — theme sheet
SELECTED THEME: _______________
TYPE: classic / block (FSE)
LAST UPDATE: _______________
RATING / INSTALLS: _______________
SOURCE: official directory / reputable developer
WEIGHT AND SPEED CHECKED: yes / noUnderstated showcase
A minimal block theme showcases the photos without clutter.
Shop
Choose a WooCommerce-compatible theme that is light and maintained.
Blog
Prioritise readability: typography and column width.
Zero budget
Recent Twenty themes are free, understated and maintained.
✓ Best practices
- Choose a light, recent theme.
- Install from the official directory.
- Always preview before activating.
✗ Common pitfalls
- Downloading a pirated theme.
- Choosing a theme based on spectacular demos.
- Activating without checking the mobile rendering.
Key takeaways
- The theme changes the whole appearance of the site.
- Block theme = FSE, the modern direction.
- Install only from an official source.
- A good theme is light, up to date and understated.
48h Challenge — apply tomorrow
Compare three themes from the official directory on four criteria (weight, updates, rating, block compatibility). Install the winner, preview it, then return to the current theme without losing anything. 20 minutes.
- I can tell a classic theme from a block theme.
- I choose a theme on objective criteria.
- I install a theme from a safe source.
Frequently asked questions
Can I change theme later without losing my content?
Yes: the content (posts, pages, media) stays intact. The appearance and some theme-specific settings may change; you need to check menus, widget areas and templates after the switch.
Are free themes enough?
Often yes: recent Twenty themes and several free block themes are understated, maintained and FSE-compatible. A paid theme is justified by a specific design or support need, not as a matter of principle.
Why avoid pirated themes?
They may contain malware, backdoors or malicious code, and receive no security updates. The apparent saving comes at a real risk to the site and the client's data.
Samir has to choose a theme for the workshop. Which theme should he favour?