I do not have any personal experience with the Rabbit Hole website, but I can at least direct you in creating an F-List. The first thing that you will have to do is head over to their website
HERE and create an account with them. Once you have registered, they will do the standard tap-dance with you of sending you an activation e-mail and requesting (demanding) that you fetch your e-mail and activate your account. Easy enough.
From there, click on the 'Characters' tab across the top banner of the website, followed by the option 'Create a New Character'. You will be prompted to enter the character's name, which is wholly unimportant if you plan to use it solely for your account here on BMR. After that, it is a matter of adjusting your kinks, which is fairly self-explanatory. Personally, I prefer F-List as it is more in-depth, offers more options in general, and allows for the creation of custom kinks to be used in your profile if there is something that you are into that is not listed.
If you are looking for something clean and simple, Rabbit Hole may be a better option, but I cannot aid you there.