Schema Design with Mongoose

Hello everyone!

I am pretty new to mongoDB. I am working on the CRUD for a mobile app using mongoose, express, and node. I have everything set up and I am ready to start building my endpoints but I was hoping someone could take a look at my mongoose schemas / models before I begin as well as the overall file structure.

My application is an app that connects local nail techs with clients. Clients should be able to book appointments for different services and the nail techs should be able to set their own hours and time off if needed. As I mentioned before, I am just doing CRUD so I tried to keep it as simple as I could as this is just to familiarize myself with mongo and Mobile app development.

Here is the link to my repo!
GitHub - christina0902/NailTech

Thanks in advance to anyone who reads this!