Ohhh
First of all: Welcome new piggie babies , take your seat in the SuperFurryAnimals (Small Pets) Hall of Fame.
Squuueeeeee
They'll need MN Nicknames (to preserve their identity) 
Are they sisters? Who's the bossy one?
Answer to the ramp question.... my GP1/GP2 had a wide,shallow carpeted ramp going to the top of the carpeted lid of their haybox . They never cottoned on to it. If we put them on the lid they'd potter down as fast as their little food seeking egs would take them (they were adults).
When we got tiny piglet GP3 , he wouldn;t use the ramp except to hide under it. We took it out after that.
Some pigs, especially young agile ones will grasp using a ramp quite quickly . But it needs to have grip and not be too narrow or steep. They aren;t really agile animals.
They'll be nervous in the early days so might not even want to poke their faces out of the sleeping area.
Food, Patience,Food, Routine and yes Food is the way to win them round.