Rice size dab on the center, some say use a line.
Line works, dab also works. Just put it on and let the heatsink spread it out.
There should be leads from the case that go onto the mobo, refer to the mobo manual for the USB header area.
CD-IN is for older CD drive's audio function. SPDIF I/O is the in out of the SPDIF digital audio signal header. LPT is a parallel interface. COMA is a memory architecture. PWR_LED is for the power light on the case. FDD is for floppy disk drive.
For front panel, those are the connections for the case leads.MSG is for message, PW is for power, HD is for hard drive activity, RES is for the reset button, and NC is for "no connection?"