How do I access second tuner?

I have a TiVo Series 2 DT Model TCD649080.

I receive TV via a local system (MTS TV) which uses IPTV technology.
A single box (Motorola RG2400) provides 3 independent channels (tuned at 
4, 8, & 11) at once.

Currently, I have connected Motorola S-Video out to TiVo S-Video in, and 
Tivo S-Video out to my main TV set. Co-ax runs from Motorola box to my 
second TV on another floor.

Is there a way to use the second tuner on the Tivo to record two TV 
shows at once? Perhaps connecting Co-ax from Motorola to Cable input on 
Tivo?

I really wish the provided manual gave some info on this.

Thanks for your help.

Dave S.