Elixir Multiple Processes

I’m having a hard time understanding how could I integrate processes in my application. I’ve done the Elixir Guide and I hope someone can help me understand this:

Can I have a process that spawns other processes for him to do his work? This “master” process sends two values a, b and an atom :add to some process, that process makes the sum and sends it back to the “master” process? I’m looking at all sorts of tutorials but can’t find any example in this matter.

Thank you.