well first off all
welcome
and to find out almost all the info u need
check out the growfaqs and look around the site
=)
mothers are plants that u keep stricktly in the grow cycle to take clones off of
clones are pretty much branches that are cut from the mother that u use to make new plants exactly the same as the "mother" thats where they get the name "clone" (exactly like the momma)
cloning can be something that is very very useful to growing but u dont have to do it.
it makes everything about 2 - 4 weeks faster which means more bud