Replacing thermostat...need help

Alright guys, need to do some much needed maintenance on my car. How difficult is it to replace the thermostat, realistically? I believe it's stuck open right now and my car has 105k on it so it's time to refresh the cooling system. I'd say I'm a moderate DIY'er. On this car I've replaced my ZKW bowls successfully lol anda few other minor things.



Any thoughts?