Building, running tests, running locally is supported on Linux and macOS only.
go run golang.org/x/build/cmd/coordinator --mode=dev --env=dev
to start a server on https://localhost:8119. Proceed past the TLS warning and you should get the homepage. Some features won't work when running locally, but you should be able to view the homepage and the builders page and do basic sanity checks.
Render the "Trybot Status" page locally
To view/modify the "Trybot Status" page locally, you can run the coordinator
go run -tags=dev golang.org/x/build/cmd/coordinator --mode=dev --env=dev
Then visit https://localhost:8119/try-dev in your browser. You should see a trybot status page with some example data.