In order to tell if two terms are alike, check it’s variables. If they have the same variables they are like-terms. For example, 2kl + 3kl are like terms because they have the same variables. In order to add them, you need to add the coefficients. A pair of terms that are not alike are 3kl and 5kps. They are not alike because they don’t have the same variables.
Hope this helps!