Do you have any kind of steamer basket? If so , then put some water in the bottom of the pan, then the basket, then the potatoes. cover and boil. Keep an eye on the water level so it doesnt go dry.
If you dont have one then I think boiling them with skin would be fine.
Or you can peel and boil then mash with butter and milk.
They dont have to be steamed, youa re just making mashed potatoes.