You just heard about Omni Sidekick and want it working in Chrome, but you are not sure where it comes from or whether it needs an account.
Omni Sidekick is a Chrome extension, so installation is one click from the Chrome Web Store listing. Chrome downloads and enables it automatically. There is no account requirement and no credit card on the free plan.
Click Add to Chrome on the Web Store listing and confirm the permission prompt. Then click the puzzle piece icon in the toolbar and pin Omni Sidekick so the icon stays visible. Onboarding opens automatically on first launch and walks you through connecting a model.