Don't know how... get external ones. 
But they aren't cheap.
For RAM, cannot suka suka buy any type of RAM you want. Get your
motherboard manual out and read what type of RAM is supported, then
buy.
As for putting in, look at the hole in the RAM stick (circle in
red)
Then look at the motherboard, the RAM slots specifically. Make sure
the hole tally with the motherboard. If it does, just flip it
around (make sure the golden metal is still facing downwards)
Put it in properly, and press down gently. Make sure you hear a
click sound, this will mean the RAM stick has slotted in
properly.
For DVD drive, there's this thing popping out (circled in
red)
That will tell you how to plug in. If one way doesn't work, don't
force in. Flip it around. To connect to the motherboard, same
thing. This connects to another slot next to your hard disk, trace
your hard disk IDE cable...
