After finished HA installation there is no HACS (community store) installed (of course…). For installing, go to: https://hacs.xyz/ . Note that you have to install one of SSH add-ons. I installed “SSH&Web terminal”. Then read the manual carefully and install accordingly.
Now, once it’s installed it can (supposely it WILL) happen that you will have a message something about that HACS is still isntalling-configuring (can’t remember exact words right now) quite a while. Don’t fear, this happens because GitHub blocks connection after xy connection attempts (safety reason). And HA initially does quite some of those “connections”, since it has to refresh all GitHub data (collect all add-ons). Be patient, it can take an hour or so to be “unblocked” by GitHub, so HACS would be able to continue it’s refresh and finish installation.
After all works you’re done. EXCEPT… once it happened that i didn’t have ANY community addons, only official ones. Solution for this is this: https://github.com/hassio-addons/repository