Logic flow of dynamo

Hi All

Im new to dynamo and I dont really understand the logical flow behind the program. When you start off in a program you generally work on a flow from left to right, top to bottom. Dynamo… I dont know. Take getparameterbyvalue for example. There is element, parameter name, and var in the block. What are inputs and what are outputs?

Then Element.SetparameterByName. There is element, parametername, value and element in the block. What are inputs and outputs here?

If I could get a page or something to explain what each library item does it would make more sense

Right-click the node and go to Help
Also, read the primer.

okay bit better. What im struggling with is getting it to select elements of type 75x75x6. I dont know where to place it so select only 75x75x6 ea at the beginning

Try Element.Types or Family.Types nodes