Get an erection before pumping?

[PrimeTime21]

Hey guys recently got a digital penis pump on Amazon so I'm brand new to this. I've done 2 pumping sessions so far. Both 5-10 mins in length. I really don't know what I'm doing but I've been reading a lot and watched a few vids on porn hub. Couple questions for you guys who have experience...

Should I get an erection before pumping? My pumping has mostly got my dick erect but I feel like it could be better if I was erect before pumping?

I have mild ED but my main goal is just to improve sexual function. I'm 8" but wouldn't mind some more girth as a goal. Thoughts?