If you just need to login, go to the Login page.
If you have already registered but you still need to download the game installer, go directly to download.
Are you creating an account for your young child?
If so, you should select "Under 13"
ROBLOX has a variety of online safety features that help to prevent your child from disclosing personal information to other players. As a parent, you will have the option to override them later.