Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.
I have already built five that did not exist so yes it is possible. The process is quick if you use stock objects.
It's all included in MSFS but you need to install the SDK. You can do it from within the sim by activating developer mode.
This YT channel is very good for beginners: https://www.youtube.com/c/FlyingTheston
He starts with the basics and covers pretty much everything you need.