not fairly difficult. to restore an entire machine based off an Time machine back up, just insert your OSX Install disc, select your language and from the menu bar select Utilities > Time Machine Back Up (or Restore from a Time Machine Back Up) if your time machine back ups reside on a Time Capsule click the AirPort Icon and select Join Network and enter in your Wifi access information. then select the timemachine backup then select continue and should be able to see all the incremental back ups
If its on a external drive just plug that in and then select the drive, continue and then select the date of the back up you wish to restore.
Then should be easy to go from there.