There are many videos on YouTube which you can follow to guide you along the process. Most hardware also comes with leaflets which picture/describe how to install the parts. A quick rundown of what you will have to do:
• Put the CPU into the motherboard socket, making sure it is aligned with the triangle, and put the cooler on top, plugging it into a fan socket. Don't forget thermal paste if the cooler doesn't have it already.
• Put the RAM into the RAM slots, lining the gap in the modules with the slit in the slots. If you have 2 ram modules and 4 slots, it should be in slot 2 and 4.
• Plug GPU into a PCI-Express slot.
• Put this into the case, lining up he holes in the motherboard with the case standoffs, then screw them in.
• Put PSU into the case's PSU place, then plug the connectors into the motherboard and GPU, where they fit.
• Plug the case's front panel connectors into the motherboard. This is according to the manuals of both the case and motherboard.
• Plug monitor into GPU, not motherboard.
If there is a technical term here that you don't understand, Google will hopefully clear things up for you. The thing to remember is that everything usually has its own shaped/sized connectors. It is very hard to plug the wrong thing into the wrong place.