First of all unzip the file. you will notice that there are a lot of APKs. transfer all those apks to your phone.
after that, download an app that is called "root explorer" you will need this aplication, go and enter to that app, once you are there, select all the apks that are on CM7 themes file, y copy all the themes and paste it on " system/app ". after pasting one by one give inverted L permission. I hope you understand everything that i typed.
Reboot you phone and go to theme chooser and you will see all the themes there,
All these themes are awesome, you will like it.