Problems with my tek 492BP


I got some troubles with my TEK 492BP (B020153).
During investigations i have 2 questions:
1) how can i activate my 10 MHZ reference connected source (switching from internal to external)?
2) In the service manual Vol. 1 for the 492AP/BP i find the following string for looking at the LO 1 state => <BLUE > <SHIFT> <EXT>
This gives the error "no macro is stored at selected number". That make sense because because <BLUE > <SHIFT> markings near my front panel EXT button is talking about macro's. Could it be that the service manual is not the right one for my SA or is it just my user error?
Thanks Ben