You can change the password in Settings => Security. To change the password, simply enter the new password that you would like to use.
When you register, you can choose one of the following roles, (which you can always change):
However, if you want to not only post ads (as a blogger), but also get, for example, reviews of your videos from other bloggers – you can always switch to the role of an advertiser in the interface of the system and search for the executors you need. Just move the switch to the desired position and enjoy its benefits.