Drawing Simple Bohr Models
The video below shows how to draw Bohr models through argon.
Drawing Bohr Models Beyond Argon
Things get more complicated once you go larger than argon. Usually you will not be asked to do this but you can watch the video if you would like to know.
Bohr Model Explained
Just like you don't have to understand how a crankshaft works to start and drive a car, you don't have to understand the origin of the Bohr model to use it. If you are curious, watch the video below.