Its been a while for me. Does anyone know that key code to make 2 prims stick together?

[paleontol99]

 Does anyone know that key code to make 2 prims stick together?

I remember that Control D creates a duplicate but I do not remember what cements to parts together when you are building something.  Thanks for any help.

[Charolotte Caxton]

I know you can highlight them and choose link.

linking

ctrl L