So you have decided to build or assemble your own pc. There are many questions and considerations to you doing this from, what tools do I need to build my own pc, to what hardware do I need to install in my new computer. Of course there are also software considerations but that is more for another/different website that specialises in that type of advice.
Another consideration you must make is that, although it is becoming increasingly popular to build your own computer, why are you doing this? Is it because in most cases, it saves money or is it the sense of achievement? Or, do you simply not like the typical designs many companies use to keep you coming to them for new parts or upgrades or a limited warranty computer which may fail?
Should you tackle the project of building your own computer? Why not? Even if you know nothing about computers, but have a desire to learn then I am sure you can "give it a go". Learn the basics, don't try to jump ahead and be patient.