Jai Srimannarayana!
Ma:, is a nama of goddess Lakshmi. If it is short “ma” then it refers to the soul. This is ‘jeeva’. The meaning is one who is an embodiment of knowledge or one who possesses knowledge as his nature. It is not a manthra. Usually manthra needs to have o:m at the begining, then there should be ‘namaha’ either in the middle or at the end of that name. Then only it will be called as manthra. If you want to make ‘ma’ as a manthra then it will like ” o:m ma:thre: namaha”. or “o:m namo: ma:thre:”
one needs to look into the story of sri ra:ma as a human being. so he needs to go to a guru and learn strictly according to the human terms and conditions. whereas one should understand that lord krishna is not a human being. he came to show as and how god would be. so he, in fact, does not need to go toany guru and learn anything. yet, he also approached garga:charya while he was young and approached sa:ndi:pani for 64 days to just understand what the 64 kalas are. it is only to say that anyone needs a guru. that is all. he never got trained in any subject from anyone.