That'd take a bit of an investment of time there.
First of all, keep every newspaper stack you have. You can start teaching you dog to pee and poo wheever there's newspapers lying around.
You can also make use of those sprays, but usually it works just as well without the sprays.
Firstly, whenever your dog pees, soak some of it in a newspaper, or wipe where he peed.
Then, set a quiet area away from hustle and bustle of your house and lay some newspapers on the floor, preferably in a loo where it won't stain your floor boards or leave a nasty smell.
Leave him to sniff the newspaper for a while.
Once he starts sniffing around the house and circling the place looking for somewhere to poo, take him immediately and put him on the newspaper.
More often than not he'd poo or pee there, if not, it might take a couple of tries.
My dog Poochie took 2 tries to get that right. After the pee/poo, let him sniff once or twice, and then throw the top few layers away.
The next time he comes he'd smell the poo/pee smell and start doing it there.
Slowly, within a few day span, depending on how fast your dog learns, change the newspaper location and see if he associated the newspaper with potty.
Slowly, put the newspaper in a litterbox. That will take a little longer because he'd be used to the newspaper just lying around.
But you can introduce him to the litterbox with the paper just like how u did with associating the newspaper with potty.
There u go he's a proud paper-trained pet!