Should be in the root forum, but that's OK. ADB is accessed by typing ADB commands directly from your computer's command prompt while the Droid is connected.
Flash the kernel:
-Copy the .img (kernel) file to the root of your SDCard.
-Unmount but leave the Droid plugged into USB and turn on USB Debugging mode.
-Power down the phone, reboot into recovery (assuming you know how to do this - X and power button)
-Select "Mount Options", mount System then SDCard.
-Don't touch the phone
-Type in your PC command prompt:
adb shell
/system/bin/flash_image boot /sdcard/kernelname.img
exit
-Obviously, replace "kernelname" with the proper name of the file that you have.
-Unmount SDCard and System
-Back out to the main menu and select reboot from SPRecovery.
If your WiFi is broken:
-Download the WiFi fix
-Put it on the root of your SDCard
-Follow the process above to boot into recovery and mount the systems
-Type in your PC command prompt:
adb shell
cat /system/lib/modules/tiwlan_drv.ko /system/lib/modules/tiwlan_drv.ko.bak
cat /sdcard/tiwlan_drv.ko /system/lib/modules/tiwlan_drv.ko
busybox chmod 0644 /system/lib/modules/tiwlan_drv.ko
exit