M7310 - How to assign line 3 and 4 to button 3 and 4 ?!

[Alarmeselect]

Hello,

I have 2 m7310 phones that I added to my existing 4 lines system.

Line 1 and Line 2 are programmed, but I cant seem to set line 3 and line 4 on the next buttons ?? I scroll the feature code list but cant find anything

Thanks !!

 

[MooreTel]

It's in "Installer Programming". If you don't know how, call in a tech.

 

[cook1082]

Youtube is great for this stuff.

https://www.youtube.com/watch?v=IraMOZ8xp0Y