How can I make an appointment? i didn’t find any template that does
Take a look here
Welcome to the community.
If you just want simplified booking, then just use the date and time picket. A free app which Teaches how to build an appointment/booking app is https://concepts.glideapp.io.
You can check some of mine out but they are not free templates. I would recommend Concepts to learn how to bring one to life in Glide.