How to introduce new bird to current one

[Newbsi]

I am about 4 weeks out from bringing Dobby (IRN) home. She will be about 12 weeks. Gollum (Senegal) will be about 5 months.
When I bring this new baby home, how should I do introductions? I am getting Dobby from the same breeder that I got Gollum from. She is very careful with exposure to her home and babies. I do not plan on quarantine.
Right now I have their cages side by side, the same exact cage.
I am just curious as to what are the right and wrong things I can do.

 

[Birdman666]

I sit them both down on my lap. Alternate attention between the two.

If they don't get along, one is on a nearby playstand, and the other is on my lap, and we switch off.