Emu XL-7 & MP-7 User's Group

I am a new xl-7 user (thank you very much)
I am starting to record my own patterns but am having a hard time 
when: 
1) I mess up recording , whats the fastest way to undo a track
or delete a track you f'd up on

and 

2) while step recording how do you get a note to hold?

thanks and peace