When my eldest son (now 4) potty trained he never used a potty he went straight on the toilet which was much easier as that way you only do it once. if you use a potty first then you end up training twice when it comes to the toilet aswel. my son never "sat" to wee either he always stood up and by the time he was three he was dry day and night. i have a 1yr old son who i will do the same way.
either way you train use a reward system. every time they wee or poo on toilet (or potty) they get a sticker. if they do it on the floor no sticker. remember to praise them every time they get it right. you will soon notice that they want stickers and will start doing it in the right place.
reward them say 5 times on the toilet they get a sweet or a toy anything to keep them interested.
But always remember to praise them make a HUGE fuss of them when they get it right.
Good luck and all the best
Hope this has helped