How do you join Hypixel for the first time?

You need a proper bought Java account to get in, cracked launchers get refused at login. If you're new to it I'd start on the latest version, the server handles older ones too but the newer client has fewer issues for most games.

it's Java Edition only, Bedrock can't connect. Multiplayer > Add Server, put mc dot hypixel dot net as the address (typed with real dots), save and join. Pretty much any version from 1.8 up to current works. you'll spawn in the main lobby, use the compass in your hotbar to pick a game. the server will also ask you to accept a few rules the first time, that's normal.