Puppies don’t have full control of their bladder or bowels until they are 8 months old. So, don’t be too upset if they aren’t getting it straight away.
The keys are:
Taking your puppy outside (Or to their designated spot) every hour or sometimes less, is important. When you take them out, wait at least 10-15 minutes for them to go. Don’t give up too quickly, even more so if they are distracted & playing. If you were to give up and bring them inside, they will quickly become bored & remember they need to go, having an accident inside. Keep them on leash when you take them out, to minimise distraction & playing. Reward them when they do go, giving them your chosen command.
A big mistake is allowing them free access to the whole house. This allows the puppy too many options in where to relieve themselves or sometimes the puppy pads are just too far away to make it on time. If you are distracted & not actively watching them, you will miss signals they give you letting you know they need to go, resulting in them finding the next best place to go.
Restricting their space to a play pen or puppy proof (small) room allows enough space to sleep, play, drink, and toilet. Making them make better choices in where to go, as they really do not want to go where they play, sleep or drink. The best choice being the puppy pad they can make it to on time. Or if they are in a crate they will generally let you know a bit more loudly as they don’t want to go where they are sleeping with no space to move away from the mess. So, if you can not actively watch your puppy, put him away in his restricted space to aid in his toilet training.
Reward & punishment. Of course, don’t forget to reward your puppy when he does go in the right place. Don’t get to excited though, as this may distracted him from going, wanting to join in with the excitement. If you don’t catch your puppy in the act of going in the wrong spot, you can not tell him off! They do not understand why they are in trouble, just that you are angry. If you do happen to catch him going in the wrong spot, simply tell him no & move him to the correct spot, even if he has already finished.