When the BBS is displaying information, you can abort the display by typing control-X, control-C, or control-O. This lets you skip by information you're not really interested in.
When you're entering information, you can correct your typing by using backspace (control-H) or delete to erase the last character you typed. Note that this is the only editing facility provided at this time. Also note that you can't backspace onto a previous line.