Hey, that is (among other things) what forums are for
Glad to see you decided for the do-it-yourself option. Careful though, it can be addictive.
Unless you use excessive physcial force to bash it together, there is very little you can do wrong when assembling it. Everybody has their own preferred order in which to do things. I've bought my pc's bit by bit over time and assembled they as I received the components. Looking some like 1. attach PSU to Case (if purchased seperately), 2. Hook up the motherboard to Case, 3. put in RAM and CPU (plus CPU fan), 4. Plug in other cards (sound, gfx, whatever) 5. attach drives to Case and connect to motherboard 6. Hook up other stuff (keyboard, monitor, mouse etc.) 7. Cross fingers, pray if it helps, switch on main power
Other people do things in a different order.