Optimistic mechanics! It’s not hard, true, but on a scale of one-to-tearing your hair out, I’d rate it as ‘well fiddly’
A lot will depend on the make of brake.
First ensure you buy the correct pads -easier said than done in these days of fat finger error prone online shopping. . . Bitter experience!
Make the highly significant decision between ‘sintered’ or. ‘Organic’ -no, it’s not an environmental thing, organic is used in its chemistry sense here. It’s one of those trade offs between longevity and effectiveness. Read it up and throw the dice.
Taking the pads out of the packet be sure not to lose the fiddly spring, and keep your fingers off both pad surfaces and the disc itself. (And you do know not to use spray lube within four miles of a brake disc don’t you?!
Having dropped the wheel out, and arranged some means of supporting the bike while you work on it, now is the time to make sure you know your calipers. Back off their adjusters so the pistons are wound in so you have max room to get the pads in. If they are hydraulic, remember not to squeeze the lever or push the actuator arm or you will be refilling and bleeding the system!
Now assemble a pad-spring-pad sandwich, ensuring the spring is correctly seated. Depending on the ease of access the design of your calipers and frame give you, you will now find it ranges from tricky to almost impossible to get the pad sandwich slipped into place in the calipers, leading to several ‘pingfkt’ moments. Also, just as you master the knack you may realise your pads are an asymmetric type and you have been trying to put them in the wrong way round . . .
Once you have them in place and the wheel re-attached, (dropping a back wheel is difficult enough because, derailleur, but now you have to thread it correctly through the chain while the derailleur mech tries to eat your fingers, AND line it up with a millimetre clearance gap between disc and pads, while also guiding the axle ends into the drop outs. Being able to think in 4 dimensions helps) . . . You now have a bicycle shaped thing again, but the whole operation will have bu**ered up your brake alignment, so out with the manual or online tutorial for your specific brakes and run the whole alignment set up procedure from scratch.
Finally, don’t forget that your brakes will feel alarmingly ineffective at first because they will need ‘bedding in’. Ride (carefully!) to a nearby, but not too steep hill. When safe to do so, accelerate to a moderate speed downhil, then apply the brakes to gently slow you to a walking pace, but not a full stop. The idea is to ‘wipe’ the pads all the way round the disc a number of times, without leaving any gaps or ‘hotspots’. Rinse and repeat until braking feels good again.
There, really simple and easy isn’t it! Well, yes, in the general run of bike maintenance it’s no biggie, but the first time, like many things, may not be all that pleasant. And if anyone thinks I’m exaggerating -you should see the fuss I make about changing side-pull rim brake pads!
yep I can concur 
