Puppy potty training schedule

Hey – curious about your pups potty schedules & training.

Do you have a bell or anything by your door that your puppy is trained to ring if they need to go out? Do you just make sure to take your pup out at specific times i.e., after food time, nap time etc. ? I’m a bit confused on if I should implement something for him to let me know he needs to go out or if I just get him on a scheduled of going out at certain times.

Also, how long did it take you all who brought home your puppy at a very young age to be just about fully potty trained and out of the pen?

Thanks in advance!