Have you
really looked at the help file? Have you tried the manual? Or the downloadable Quick Start Guide (which may well be the same thing)?
OK. I'll be kind. Look up "Split".
Or even kinder....
Place your cursor over at the start of the bit you want to cut out. Press "S"
Now place your cursor at the end of the bit you want to cut out. Press "S"
Click on the bit you want to cut out and press the "delete" Key.
Or
many other ways of doing it.
HTH (if it doesn't I really can't make it any simpler for you
)