Not to be rude, but you could read the directions. Honestly, why do people refuse to read directions, but will post on a forum asking how to do it, apparently willing to read the answer? If you had read the directions, you would have figured it out within a couple minutes. Now you have to wait for a reply.
Rant over. Since deep down I am a helpful kind of guy, I will go ahead and answer.
Easiest: Use Instant Handbrake. It's on the Handbrake website.
Most configurable: Put in the DVD. Close DVD Player when it launches. Open Handbrake, click 'Open', click on the 'Title' drop-down box, and select the longest item. (Usually that's the movie.) Select what chapters you want. (Usually you want them all.) If it's a DVD of a few TV show episodes, then they are probably listed as separate 'titles', each just under half an hour or an hour, depending on the TV show. Just repeat this process for each title. If you want a larger, but MUCH faster to rip file, select 'MPEG-4 Video / AAC Audio' from the 'Codecs' box. If you want a smaller, but MUCH slower to rip file, select 'AVC/H.264 Video / AAC Audio'. In the 'File' text box, type the name of the file. Click 'Picture settings...', For a new iPod, and the best picture quality, click the 'Width' down until it reaches 640. If you have an older video iPod, or just want smaller files, keep going until the width reaches 320. If the source was a TV show, and the picture has funny sideways lines, click 'Deinterlace picture'. Click 'Close'. Set the 'Average bitrate' based on how high quality you want the file to end up. 1500 is the maximum that an iPod can play in H.264, 2500 is the max in MPEG-4. (An MPEG-4 at that rate is still a worse quality file than the 1500 H.264.) Both of those are for 640 wide video. If you went with 320, halve those. If you want a lower-quality, but smaller file space file, I would say go as low as half those maximums. (To as low as 375 for a 320 wide H.264.) If you want a higher-quality file, but one that will take twice as long to encode, check the '2-pass encoding' box. Click 'Rip'. Wait.