First thing you need to do is breath, CBR stands for "can be replaced", You went down, and your alive. I am in the middle of a rebuild myself, so i understand how frustrating it can get.
First thing i would do after i checked the battery is, remove the plug that is inserted in the back of the gauge. then, reinstall it. See if the bike turns on.Then make sure that the fuse is not blown.
these are a couple of easy ones that have F*ed with my head. if it's not this, were going to have to do a little more hunting.
What does it do when it does not start? Does the pump prim?
This is what the service manual ask
1 Is the fuse blown
2 is the battery in good condition
3 does the starter relay switch "click"
4 Does the starter motor turn
5 check relay coil ground wire lines
6 Is the starter relay switch operating correctly
7 is there continuity on the starter relay switch
Let us know, and good luck!