drop down selection to auto populate multiple cells

Hi All,
This is my first post. I know what im trying to make but i have no idea how to get there. i have read alot on here about similar problems but no one has been able to answer with enough detail for me to understand so im hoping posting will get me there.

What im trying to do is have the selection from a drop down menu auto populate multiple cells
I have three selections from the drop down menu and then i have three different "sections" i would like to auto populate based on the first selection.

for example
First selection would be contract type A B or C
for each contract type there is a list of Inputs, Outputs and Processes

So if you select contract type A then the relivatn inputs outputs and processes would populate.

Can you please help me with how to set this up

It is hard to conceptualize the project without an example but the basic idea is as follows:

1. Set up a userform for each possible selection
2. Call on the appropiate userform from the dropdown menu selection
3. set up a macro for each possible selection that will process the input and render the desired output in the proper place.