I agree that you should not push the issue. Unless he's shown a real interest in the toilet, wanting to have no nappy on, has some sort of awareness of when he's wee'd or poo'd or needs to wee or poo (eg my DS1 used to go to his pooing place- behind the lounge- to poo, so I knew he was aware of the urge and when he wanted to go, I would take him to the toilet to try to do it, then his nappy went back on after 10mins or so whether he's poo'd or not, but for us, it all just sort of fell into place after that).
If you want to try to encourage awareness of toileting procedures for him, then take him to sit on the loo a few times a day, maybe read some toileting stories while he's on the toilet ect. But unless he's shown some sort of readiness it might cause more harm than good to train him before he's ready, or at the least, it will just take forever and you will constantly be cleaning wee and poo out of undies!