Use the app from the Google Store called 'Rom Manager.' It makes everything extremely easy and straightforward.
1) Download the app
2) Open the app and make sure you have the latest version of Clockwork installed (it will show you in the app)
3) Make sure to make a backup of your stock system first so you can always get it back if you wish (can do this in the app as well)
4) Hit Download Roms, and pick Cyanogenmod 10 and choose the file name you wish (either the nightly or the M1 version)
5) It will open a dialog box asking if you want Google Apps as well (obviously you do so click the box if not already)
6) Thats it! It will download the files and then reboot into clockwork, installing everything on its own
Everything took about 10 minutes for me (backup was about 6-7 of the 10 minutes). If you have any other questions, let me know!