For information on setting up or using Gold, see these docs.
For an architectural overview, see: https://docs.google.com/document/d/1U7eBzYrZCPx24Lp9JH2scKj3G8Gr8GRtQJZRhdigyRQ/edit
To run Gold locally, run a local target defined in BUILD.bazel. E.g. bazel run //golden:skia_infra_local. Then run make run_auth_proxy_before_local_instance. You can then access the local Gold instance through http://localhost:8003 with the current user authenticated.
Gold uses CockroachDB to store all data necessary for running the backend servers. (Caveat: We are in the middle of a migration towards this goal.)
For production-specific advice, see docs/PROD.md.