Get A Crate!!! We have been raising Terriers for over 38 years and that is the first thing we tell everybody. You need a crate that your puppy can comfortably stretch out in and stand in. You do not want it to big or they may potty in it.
Next you need to get a schedule. Puppies at 4 months need to be fed twice per day. After feeding the puppy must go to his designated potty place. Do not play with your puppy at this time. You should plan on spending upto 15 min. trying to get him to go when you first start. Once your puppy goes be sure to make a big deal about what a good puppy they are and give them a treat. Always use the same word when trying to get them to go. The puppy should have nothing to eat or drink at least two hours before bed. They are going to need to out as soon as you get up, after naps and after hard play or eating. When your puppy is not in the same room with you they are in their crate. Do not give them the run of the house. At four months they should be able to go upto 8 hours overnight without having to out, but if they fuss during the night get up and take them out. Do not make this play time. It is in and out for potty only and then right back to bed.
The main points are Crate, Schedule and Consistency.
Next you need to get a schedule. Puppies at 4 months need to be fed twice per day. After feeding the puppy must go to his designated potty place. Do not play with your puppy at this time. You should plan on spending upto 15 min. trying to get him to go when you first start. Once your puppy goes be sure to make a big deal about what a good puppy they are and give them a treat. Always use the same word when trying to get them to go. The puppy should have nothing to eat or drink at least two hours before bed. They are going to need to out as soon as you get up, after naps and after hard play or eating. When your puppy is not in the same room with you they are in their crate. Do not give them the run of the house. At four months they should be able to go upto 8 hours overnight without having to out, but if they fuss during the night get up and take them out. Do not make this play time. It is in and out for potty only and then right back to bed.
The main points are Crate, Schedule and Consistency.