Suppose that an amateur mathematician finds a solution to a major unsolved problem and they have written their full proof and would now like to publish it somewhere or at least have it critiqued by the professional community. What steps should they take? Additionally, lets say that the proof in question is completely correct (morally true) but is not formally rigorous (ie it has a lot of writing that could be converted into symbols). Would a journal accept this proof or would they demand that it has to be fully-formally rigorous? What steps must be taken so that they can accept the proof for publication?