Twitter Help....

I hate starting new stuff because some people are just sooooo mean when you ask for help. I started tweeting so my sister and I could talk {without kiddos ears} Well she is new too,{not as shiny & new as me} but doesn't really know everything about Twitter. Sorry my ADD took over- If someone could please help me better understand this "TWEETING" I would really appreciate it!! The older I get the more advanced and harder they make all of this shit:{ Chucky is more advanced then I, but I don't want him to know about Twitter until after Christmas LOL!
THANKS!!!