VisualSubSync basic tutorial Video
How to proceed after you've followed these easy steps (phase A only).
Don't go over 4 seconds, 5 seconds tops if you really can't split it, and 40 characters per line maximum (ideally, but you can go a little over that of course). To type a second line, simply press enter, like on a typewriter ;-)
VSS will save your subs in an .srt file. Your video will play with the subs provided both files have the same name (one with an .avi and one with an .srt extension), and that they're both located in the same folder.