One of the great things about Pomeranians is that they are relatively easy to train. This holds true for potty training just as much as it does for basic behavior and tricks. The biggest thing to keep in mind is that your Pom will react far more readily to consistent training. Your Pom needs to be trained to go potty outside and he relies on you to provide the necessary training. This is where consistency truly pays off; if you keep changing your methods of training, your pup will remain confused and may never master the art of peeing outside.
The job at hand is to teach your Pom that going pee, or for that matter poop, in the house is not acceptable. However, you must have realistic expectations. Your pup is not going to master this vital skill overnight. By rule of thumb, a Pom puppy can hold themselves for "one hour per month of age" up to a maximum of six hours. An adult Pom can hold themselves for up to eight hours. You should never leave your pup for longer than eight hours.
The first thing you need is a way to restrict your pup's access to the house when you cannot be there to supervise him. The best way to do that is to use a training crate. This will be used when you can't supervise your pup or when you need to be gone for an extended period of time. Beyond this, you will only need a few extra supplies, including a leash and treats. For one method, you'll also need potty training spray, which is available at most pet supply stores.
Of course, along with these, you will need plenty of time and patience to work with your pup until this vital skill has been mastered.