Q.Growing a mango tree from seed
I have a mango tree that will be completing its second year of growth this August/September. It is slightly over 5 ft tall and straight with no branches. It does, however, have all of the leaves it has produced since emerging from the seed. My 2 questions are these: how do I force it to produce branches, and when should that be done?
My present thoughts are that I need to cut the top of the newly forming main shoot just shortly after the new reddish leaves turn green. I would really appreciate your help here.
Thanks,
Gary

Pruning for shape and production begins when the tree is 4 years old.
Here is an article with more information.
https://www.gardeningknowhow.com/edible/fruits/mango/growing-mango-trees.htm