Yapmak is a verb. We can use it instead of make and do. For example, make a salad: salata yapmak However, etmek is helping verb. For example, leave: terk etmek help: yardım etmek Sometimes, etmek can be simile. For instance: What did I do? means Ben ne yaptım? but also we can say Ben ne ettim? But second sentence is not useful and formal. Some people can support that yapmak is helping verb but when we use yapmak instead of a verb without make and do, it must be idiom. By the way, other helping verbs are etmek, olmak, eylemek, and kılmak. Usually, we don't often use eylemek and kılmak.