we housetrained our puppy from 8 weeks and what the others have said is fantastic advice.

we got the wee pads from the pet warehouse, but paper should be fine too!

after each meal, take them outside and encourage them to do a wee and poos. so for example we would say to her 'do a wee' or 'do a poo' etc etc and the moment she started to squat down to do it we would say it again (to get the recognition that what we were saying referred to her doing her business). also a great idea to get them to do it all in the same area as it helps with them recognising why they are out there ITMS (we also had her on a leash so that she wouldnt just run and play...that time was for wees and poos).

also, if there are accidents off the mat inside, make sure to clean it well as the smell of wee especially lingers and the dog may keep weeing in that spot as it is kinda like a 'toilet' spot lol!

oh and just before bed time too...take em out for a toilet stop.
it sounds time consuming, but we didnt find it that bad really and they learn quick.