Total newbie interested in triathlon...need advice

Okay, so I'm new to swimming. I swam for a team when I was a kid, but my version of 400 IM was so terrible that lifeguards were probably tempted to intervene. I'm a pathetic (stroke-wise), but strong swimmer. I taught whitewater kayaking and I'm well-trained in both lifeguarding and whitewater rescue. I completed more than one multi-day rescue courses that literally required me to jump in a nasty, man-eating hole, strip off my gear, and crawl to the bottom of the river only to be spit out and make my way to the river bank after saving a hypothetical "victim." I just registered for my first triathlon. Can anyone tell me how to begin training? My husband is a "retired" D1 (and world ranked) swimmer who is more confident in my abilities than my own mother is. I know better than to listen to him. So I'd like to hear what you have to say about how I should begin training for an Olympic-distance tri, given this: I am a strong (but NOT pretty swimmer) and I currently run 7-8 miles a day. I also mountain bike probably 30 miles a week. I'm not looking to place in this triathlon, but I hope to finish with a respectable time. Where should I start?