Usually I like to give the receptionist a 32-button phone. The sixteen center buttons I would use for CO lines, Voicemail and ICM, etc. and the 16 buttons on the right for Direct Station Selection/Busy Lamp Fields (DSS/BLF)
But since you're working with an 8 button phone -
On SAT
Go to Basic->Terminals->Multi-line (Alt-BTM)
then select Line Key (second tab)
Select the receptionist's extension from the top right hand
On the left you should see LK# 1-12
You will only be working with the first 8
You will setup Feature access keys. For buttons that are already programmed like you call arrival keys (SIE) leave them alone.
For any available buttons select FA, you will then be prompted for an FA number, just work yourself up from 01 (01, 02, 03, and so on)
Once you have done that and uploaded the database, go to the receptionist's phone and for the buttons you setup as FA do the following:
Feature->Redial->"Press the Button"->Dial 1->Extension# of the extension you want to see
If you are not sure about what is currently programmed, just reply to the thread and let me know.