Uhm I couldn't find this in manual, so here it is.
"A" is select, jump.
"S" is attack.
"Enter" is Start (Game Menu).
"F" in menu brings 4 options Communication,Equipment,Navigation and Data view.
The room which has a platform in the middle (after going through a "S" named door) press the up arrow key to save.
Arrow keys to move.
Idk if there are other keys, haven't finished the first boss