Guten Tag:)
만들다 basically means “to make something” and
하다 means “to do something.”
However these words are so basic that you may face a lot of variations about them in conversation.
For example, when I say “숙제를 하다”, that means “to do homework”.
But if I say “요리하다”, in this case, that means “to cook”.
So there might be two kinds of “하다”.
First meaning of it can be “to do something” and the second meaning is the korean suffix that describe the stem of verb such as “~하다”(요리하다).
Ich hoffe das hilft:)