Trimming

First time growing, I have one seedling, one vegging, one just starting to flower. I've been trying to understand a little bit more about trimming. I don't understand what I should trim or if I should even trim anything on any plants. Just need some simple advice or some links with good info.
peace and love

You can top or FIM to change the stature of the plant, producing more colas. Read all about it here:

https://www.rollitup.org/advanced-marijuana-cultivation/151706-uncle-bens-topping-technique-get.html

You don't have to trim, just let it go natural - a lot of people do though to keep plant height down and more manageable for smaller indoor spaces.

I have pruned, so I think I pass on topping then?

I have to highly reccomend topping for 4 main colas. I'm 4 weeks into my 2nd grow and the one plant I topped VERY Early is doing the best of all my plants in bloom right now.

If you cut the main growing stem, then you have topped. This will cause the plant to be more squat and the side branches will take over and become the new tops.