Once you clicked start on MHWALKER you create your boat and get on it, then click INS which should start the bot.
To use the binds...I guess I should explain a little bit about the keys:
KP_PGUP = the key pad's page up, etc.
I'm not too sure about your problem, it seems like everything is fine except for the fact you don't press INS so the bot starts running.
If you don't want to use the bot you can just use the bind keys to get god mode or one hit kill, etc.