CyanogenMod has been replaced by LineageOS, and there is an unofficial Nougat ROM available.
To install it, hold the power, volume up AND volume down buttons simultaneously until you see the Google boot logo, then release the buttons.
Once you see the little droid dude lying down with his guts open, use the power button to select Recovery Mode and boot the tablet in to TWRP.
Once in TWRP, plug it in to your computer. It should find the tablet and mount it. Copy the zip file containing the ROM to the root of the drive (labelled 'Internal Storage'). Also copy in any other stuff that you can/must flash (like GApps).
In TWRP, select 'Install' and choose the ROM zip file and use the slider to indicate that you're serious.
Once flashed, run the 'Clear Dalvik cache' and go 'up' and run the install again, this time on the GApps image.
You should be able to boot in to the new OS now.