Using a secondary fermentor is often an unnecessary step. The main reason for using a secondary is to get the beer off of the yeast cake, but this is really only a major issue when you are planning to bulk age the beer for months after primary fermentation is complete. It can also be used to help the beer get clear, but really it's not especially important for most brews.
The use of a glass carboy is not necessary, either. You can really use any fermentation vessel that you want. Glass is non-porous, and that's why it's recommended for long-term conditioning/aging/etc., but if you wanted to do a few weeks of secondary using another plastic bucket, it wouldn't be a problem.
For your kit, don't worry about it. Give it 2-3 weeks in primary, transfer it to your bottling bucket, add your priming solution per the directions (unless you're using carbonation tablets) and bottle. Just make sure that your bottling bucket, tubing, and bottles/caps are all well-sanitized before you start.