Build
Build is where you pick or create the two GSS-owned resources that the rest of the setup is configured against: a server GTM container (it'll run on Cloud Run later) and a test GA4 property (the destination GSS forwards events to during validation). Build does not deploy infrastructure — that happens in Cloud. Build only binds and validates.
Both Build steps are dependent bindings: changing the Audit primary bindings (browser GA4 property, web GTM container) clears Build's selections via the Tier 2 cascade and you have to re-bind here. That's by design — the server container has to live in the same GTM account as the web container, and the test GA4 property is meant to mirror the browser property's settings.
Step path: Server GTM Container → Test GA4 Property
Server container vs. test GA4 property
The two resources Build creates have different lifespans.
- Server GTM container — permanent. The container you bind here is the same one that goes through Cloud, Connect, Publish, and into production. There is no separate test container.
- Test GA4 property — temporary. It receives forwarded events during validation so you can compare the server-side path against your browser property without touching production data. After Go-Live, it can be retired.
Same-account constraint
Both Build bindings must sit in the same Google account as their Audit counterparts. The server container must be in the same GTM account as your web container (workspace operations later in Connect rely on it). The test GA4 property must be in the same GA4 account as your browser property (so the comparison isn't apples-to-oranges and the same admin can manage both). The validation checks on each Build step enforce this.