How do you say in Finnish: "Set and maintain boundaries"?
Translation isn't easy. In most cases, you need to know more how and where the sentence is used. Like in this case: what kind of boundary is being set and maintained? A literal boundary line between neighbours or countries? More abstract concept, like personal boundaries in a certain situation?
Perhaps "Asettaa ja ylläpitää rajoja" would work in both cases? If this is about personal boundaries, I might add a possessive affix.
The proposed translation is a good example of what happens when the context is unknown. The word "ylläpitää" is based on Swedish expression "upp(rätt)hålla", and doesn't sound good Finnish, never has. Even "pitää yllä" is better than "ylläpitää". But if you want to find a proper Finnish word, I would give "pysyttää", "vaalia" or "varmistaa", and depending on the context, many others would be more suitable.
Not to mention additional factors such as it being unclear whether "Set and maintain boundaries" is supposed to be an imperative sentence or not.