1. It is possible, of course, to just write up a summary of what most scholars think what happened. There is, however, a great deal to be gained for you to look at the evidence for yourself and to make up your own mind on the matter. There is nothing like first hand acquaintance with the facts of the matter. Hence this exercise.
2. Many attempts have been made to reconstruct a story that makes sense of all these various facts, all of them involving the partitioning esp., 2 Cor into blocks of text that are supposed to be the "sorrowful letter," etc., or that. For a popular example, see William Barclay, The Letters to the Corinthians (The Daily Study Bible; Edinburgh: St Andrew Press, 1954) whose reconstruction is summarized in David Prior, The Message of 1 Corinthians (BST; Leicester:Inter-Varsity Press, 1985) (see also, C. K. Barrett, The First Epistle to the Corinthians 2nd ed. (London: Adam & Charles Black, 1971) for a summary of older reconstructions). While interesting these constructions are at best the creative imaginations of the reconstructionists. The fact that many of them make good sense on their own means that we have no certainty as to which is the correct one. The most important question here is, of course, whether 1 Cor makes sense as it stands, and it does. Commentators are as much in need—as the Corinthians Christians were—of being told by Paul to "not go beyond what is written" (1 Cor 4:6).