Pick the engine you bought. Every path starts with the same download and Portal token.
Download the app from the Portal, install it, then generate an Agent token under your account menu and paste it into Settings → Portal.
API: add SMSPool, Salamoonder and Revolut or card keys under Account setup, then use “Add account”. A pasted refresh token works if you already have an account.
Emulator: create an AVD from a template in Settings, boot it, and sign in to Whatnot on it once.
Phone: enable wireless debugging, pair it, and let the app name it.
Apply the starter list, leave the daily cap alone, and watch the first day. Raise the cap or add members once the fleet is stable.