I have 35 steps to get the dogs outside, it sucks. I carry the babies out until I think they are big enough to not get run over by the big dogs. Then I work them on the steps by themselves. Once I decide they are going to do steps, I put a treat on every step of one section of the stairwell and then sit on the landing with a book. It can take them a long time (hence the book). Many figure it out on their own that way. And when they do, we have a giant party at the bottom. If they really don't get it after several attempts, I just put them on a leash and pull them down, then party at the bottom.
I would leave him up there if he goes up and then whines. If he wants down bad enough, he will figure it out.
I know you said that he is able to do 2-3 stairs...what if you put him on the 4th stair (from the bottom) and call him down? I would do that and reward him when he got down. Then slowly add more and more stairs until he can come all the way down.
I do the cross between the both. I start them on the 2nd step and work downwards increasing the step each time, however if they pull the Im gonna run back up instead of heading down, they get the leash. I also have a crap load of steps here as well...they learn them starting at 8 weeks....