Hi Mike,

First get a battery wire brush, and clean the battery posts and cable clamps
shine up the piggy back smaller heavy red wire clamp end at the positive terminal.
(That's the lead that sends +12V to the dash)
Verify that the battery cable ends are clean and tight and look at the crimps where the ends accept the wire, you don't want to see signs of corrosion and discoloration. That's the + and - wires
If you don't get idiot lights, and you have 12.6VDC at the battery (Measured at the clamps and not the battery) Then you may have a crapped out ignition switch
or a relay. (in my 1995 850 the overload relay 15+ 2/31)

Get the Volvo wiring diagram for your model, And everything you need is there
to troubleshoot electrical. You can look for the same or similar arrangement
which should include the ignition switch and a relay. If you have the same overload relay as my 850, it's easy to jumper two relay socket pins and see if
that lights up your dash, to confirm that's the problem area.

I hope that you got service records with your new Volvo, to make sure that you
know when you need stuff like the Timing belt!

Bill