How many profiles you can hold is set by your plan: Solo includes one, Studio supports up to three, and Signature supports up to ten. Add them from the Profiles page, which shows your count against your limit, for as long as you have room.
A profile holds the agent's headshot, name, contact details, license number, brokerage name, and brokerage logo. The headshot and the logo are the parts that appear on your content.
Video cards use a deliberately neutral black and white treatment, so there is no per-profile color to set. The call to action is not a profile field either: it is written per tour, on the Closing step, so it can suit the listing rather than being fixed to the agent.
When you build a tour you choose which profile it belongs to, and that agent's details are applied to the opening and closing cards for you. The account owner can do this for any profile on the account, so one person can produce for a whole office.