Two year old labrador and getting a Jack Russell

I now have a 2 year old male Labrador Retriever. Since I am home all day my lab gets lots and lots of attention. I will be getting a Jack Russell (female) in a few weeks.

How should I introduce this new puppy into the house, without upsetting the lab. My lab is well socialized as he has gone to the dog park since he was a pup and I've noticed he is quite gentle with small dogs.

Also I have a large fenced in yard with a 6 foot chain link fence. How should I further secure the yard, as never having a Jack Russell I don't know how far they will go to escape.