You don't have the IR hardware & Remote control that comes with the Media-Center Package.
Without the media center package you try it the old way...
On your cable there is an option to use the COAX output that can be set to Chan-3 or Chan-4.
The connect the COAX output of the cable/sat box the COAX/TV input of 2250. Set the 2250 to Chan-3 or Chan-4.
To change channel use the cable box remote.