You'll need a screwdriver, a replacement knob, and some patience. I've done it, so I know you can if you take your time. I am always afraid I will forget something so I take pictures as I dismantle anything (it's why I 'm the one who reconnects all our electronic stuff). I often watch a video before I do something like a doorknob to make me more confident, since I don't do doorknobs often.
Yes you tube has videos on that.
Do you want to replace just the door knob, or the whole mechanism with lock?
It's not very hard. Make sure you place the latch in first and that it is the correct size. There are usually two size settings on the latch to accommodate different doors. The instructions that come with the new knob will explain how to switch the setting. The hardest part is lining up the screw holes for the knob itself. Just take your time. The first go is the hardest, then it gets easier. ☺