Go to Wal-Mart, pick up some of these and some long ass cables, and test it out. I've heard that more splitters results in a weaker signal, so if you have cable internet, connect it to the first splitter.
Edit:
since you want a retard description, here you go. Figure out haw many TVs and/or modems you want to connect to (if you have 3 TVs and 1 modem, that would be 4). Buy a splitter with at least that many "OUT" jacks. Next, find out where your cable jack is and figure out how far away each TV and modem is. Buy a cable for each length that you measured and a relatively short cable to connect your wall jack to the splitter's "IN" jack. If you have so many TVs and/or modems that you need more than 1 splitter, make sure to buy an extra cable to connect one of the first splitter's "OUT" jacks to the other splitter's "IN" jack. If you have to use more than one splitter, connect the cable modem to the first one.