No, not difficult. I drained and refilled mine but didn't flush.
1. Release coolant reservoir cap.
2. Undo the tap at the bottom LHS of the radiator(you'll see it OK from underneath).Obviously, make sure it's not scalding hot.
3. Run the engine briefly after draining to make sure it's all out.
4. Tighten tap back on (BE CAREFUL- I broke mine overtightening it,it's plastic). If you do break it off it won't leak, you'll just need a new one for next time.
5. Fill with 50/50 Volvo coolant & distilled water.
6. Run the engine for a few minutes and top up.Check the level again after the first few drives.

There are some release valves on the back of the motor which you are supposed to undo to drain the coolant from the motor as well as the tap on the radiator. I really wasn't sure where to find them/what they look like so I didn't go messing. If your fluid is really bad, you might want to do the proper flush, not just a drain. If you search here and www.volvospeed.com you will find info on flushing.
Hope this helps-have fun.
Rick.