How do you properly introduce two cats to each other for the first time?

[Kenzie]

I have a 16 year old indoor cat, who has been my only cat her entire life. Now we are adopting an abandoned cat who is somewhere between 6 months - 1.5 years old. She is friendly and we are planning to take her to the vet for check ups before the two cats meet. They are both females. How should I introduce them so it is less stressful on the both of them.
Should my older cat eventually accept the newcomer? Even if she hasn't really encountered cats before and she is 16?

 

[DAEP11]

I kept my new one in a kennel with a litter box and another box so he had a place to sleep and hide. This way the orginal kitty could smell him and get used to him before he was loose in HER house. It also kept him from getting overly stress by a new place. I only let him out while I could supervise him 100%. It took a little over a week and they are now best of friends and never very far from eachother.