There is no Rocket-Science regarding warming up accounts. You just have to use it as if it is your personal account. What would you do with a personal account? You need to verify a phone number with it, assign a new phone to it, if you are operating it in another country than the one you are staying in, you will also need a mobile 4G or 5G Proxy. Additionally, you will also need to use Anti-Detect browser like Dolphin. Once all of these are done, you need to communicate with people, send friend requests, be able to receive some, make posts, real people's posts. Yeah, that's how it is done.