Registering an Account
Before you can play in a CTF hosted on the Hack The Box platform, you'll have to register. Navigate to the CTF Platform, and press the Register button.
Fill out the details of your CTF Platform account. Keep in mind; this is a separate account from your main Hack The Box account. Additionally, the email you use here is what will be used to contact you after the CTF for prizes or certificates.
Once you're registered, you will need to create a team or join an existing one. To create a new team, click the Create A Team button, and you will be brought to a team registration form.
Fill out the details of the form, including your Team Name, Team Motto, Team County, and optionally Team Discord. Then press the Create Team button.
From here, you can either join a CTF as a one-man team or allow others to join your team and tackle Challenges together. You can't directly invite others to your team, but they can join you by searching your team name and requesting to join.
Joining a Team
To join an existing team, press the Join Other Team button (or the Join Team button if you aren't already in one), and search for the team name. Once you've verified that you've found the correct name, please select it from the drop-down list, and press the green Join Team button.
The Team Captain will have to accept your join request. They can do this by selecting their team, clicking on the Members tab, and pressing the green checkmark next to your name.