There are many many different combinations of parts that you can buy, but it is the same principle when building a PC even if you have completely different parts. It is a lot easier than you would think, and is fun to do. You don't really need experience to build a PC, and you would save a lot of money by doing it yourself.

is there any easy mistakes that would break something?

Not really, as long as you're not careless, you can usually get warranty where the sellers will replace any p[arts that you damage when installing.

We all have done it for a first time and in my experiences, it went smoothly and it worked first time

There are easy mistakes you can make that can damage parts, but as a general rule its read the manuals and dont force parts unless you are certain they are supposed to be.

If you're from the UK and decide to buy parts from scan they have this thing called scan sure, where you can insure the basket for a short period of time - 28 days after delivery.
This covers all accidental damage including water damage.




If you don't want to order all the parts from scan I'd personally order just a few main parts from there such as

CPU (easy to damage pins etc),
Motherboard(easy to damage tracking, which voids standard returns)
GPU(another main expensive part)

I've taught three years of summer camps at a school with about ten 8 year old kids each and never had a single component fail or break. They build the whole PC themselves. If I help, it's with the larger PSU cables which can be difficult to insert.

Kids are easy to work with because they don't act like they know everything. People break things when they think they know what they're doing and don't look/ask for help.

Follow instructions, don't force anything, watch guides, find someone who knows what they're doing. It's so easy.

Nasur
Baseball

I even walked these noobs through building their PCs over Skype text chat

NASA got angry when he couldn't find the thermal paste in the CPU cooler box and Baseball didn't use motherboard standoffs at first, but otherwise no problems

I watched a video where a 5 year old built one (with parental supervision of course). Its just like legos not hard at all.