Hi again @jazzresin ... Once thing, patience is key.
Using hivesigner means you have to "import" your private key before you start using It. If you're going to use your wallet you will need to import your private active key. If you're only posting only the private posting key is needed.
Afterwards both use cases, you need to stablish a password that it has nothing to do with your Hive blockchain Keys but one that Will serve you to use the hivesigner "bridge" ( app to log in).

Keychain works the same but it's a browser extensión with added features.

Remember: switching to a different browser or device will make you start over as they are not the same instance of the app (your Keys aren't stored online).

Hope this helps clear things.