I am completely lost here

I have bitwarden extension in Chrome, but I have no idea how to get it to work with my existing logins & accounts. How can I just generate a new password for each of these? Doesn’t each site require you to go through their steps to change a password? What am I missing here? Thanks anyone.

Yes, do it and safe the new password in bitwarden.

…or just safe the old/existing passwords in bitwarden.

Whenever you login to an existing account, Bitwarden will ask you whether you want to save the Login. You can change your passwords later on, Bitwarden works with “unsafe” passwords as well.