Yes, you are supposed to befriend Salamence, here is a method which guarantees success:
When you first enter your battle with Salemance, wait for him to stop his Ground type attacks, once he stops circle him once very fast, Salamence will get annoyed and do his fire ring attack, after that he should fly around. When he is, start circling him slowly, going slow will give you more precision and accuracy, then gradually speeded up and you should be able to catch him without going through all that again, however it may take a couple of tries to get it right, so no worries :)
Hope I helped :)
