Oh, i remember the days when I didn’t know how to collect elements. You’re green!
Well, here you go. This is about 75% of what you need to know when starting with Dynamo!
There are multiple methods for selecting elements, some are more efficient than others (in terms of CPU-load.) ByCategory is very efficient. I use type-name codes (like an AIA-layer structure) to simplify filtering items i need. This could also be used with parameters.
Anyways…that should be enough to get you started. If you end up using dynamo more regularly, you will definitely need a few packages. I recommend archi-lab, steamnodes, springs, genius loci, and of course clockwork.