Create a platform for Video Calls

Hello, I’d like to create a website similar to, basically a platform where you find experts in different industries, you pay $X for 15min/30min/1h to have a call with them, once you pay you schedule a video call.

1- Is there any template existing for this? or what’s the closest template to it?
2- If it’s needs to be done from scratch, what apps you recommend having?
3- Any tips on how to approach building it?

Thank you so much!