If you want to sanitize properly, you really need to clean before you sanitize. You should clean with a caustic to remove organic soils and clean with an acid to remove mineral deposits. After doing both, you can proceed to sanitizing. Also, it's not a bad practice to do a water wash before both the caustic and acid washes.
Here's an article from a few professional brewers on cleaning/santizing:
Sanitation tips from the pros
Don't worry though, you'll probably be fine. It's very difficult to screw up brewing. I wouldn't worry about it. However, I thought it might be appropriate to give some tips.