This is something we recommend you do asap, as you will be generated a username at random by the system, it can be a bit of a pain for your friends to search for you.
Think of it like social media, if your friends join GymCube and want to connect with you but your name is ' jenny_1267 ', then there is little chance of them finding you!
So go to your 'myGymCube' in the top right of the screen, and select 'Settings'.
The first field you are greeted with is 'Display name'.
We recommend putting your full name, just like you would on Facebook or Twitter (remember that if you just put Jenny, there are likely lots of other Jenny's too), so, for example, Jenny Smith.
You can also upload a profile picture here too.