How hard is it to train my chihuahua who's 3years old to use a litter box?

I have a 3 yet old chihuahua and I'm moving into a place where it's 3 floors up and I need to know how hard it is to train my chihuahua to use a litter box? And where I get one and what do I put in it?

Cats use litter boxes - dogs don't. And if your Chi is now 3 and used to emptying where he should, outside, then I seriously doubt you'll get him to change that - and nor should he. Dogs should do their biz. outside. Otherwise as dogs don't cover what they do up, like cats do, your place is going to start to smell pretty bad. I'm afraid you are facing taking him out, floors down, regularly, or not taking this accommodation.

http://youtu.be/QvPiFcG7ROI you can train a dog to go anywhere you want if you follow these guidelines you just make the litter boxes the appropriate toilet area.

Your dog is NOT a cat. The dog should be taken outside to pee/poop - NO excuses. If you can't deal with taking the dog downstairs and outside when it needs to go, then rehome the dog to someone that will handle things better.You never ever train a dog of any size to be peeing/pooping in the house or apartment for any kind of BS excuse.

It is not hard at all to train a chihuahua to litter box train