Installation is one tag, once, for every product.
If what you want to measure is an app rather than a site, there is no tag to paste. See measuring an app instead.
1. Register the site
Add the domain in your dashboard. Skomi issues a site ID and builds a snippet for it.
2. Paste the snippet
Put it immediately before the closing </body> tag:
<script src="https://t.skomi.com/s/your-site-id.js" defer></script>
Replace your-site-id with the ID shown next to your site. The ID is part of the URL rather than a separate attribute, because each site is served its own bundle built from the products it has enabled.
3. Switch products on
That is the whole installation. Enabling a second product later changes what the existing script does. You do not touch the page again, and the snippet itself never changes.
Requests are only accepted from the domain you registered, and from its subdomains.
If nothing appears after installing, see what to check when the snippet is not working.
On a platform with no obvious place to paste it
Five of them have a page of their own, because where the tag goes is the whole question: WordPress, nopCommerce, Shopify, which also has real limits on what any script is allowed to see, Next.js, and Astro, where the tag belongs in the head rather than before the closing body tag.