Did you purchase the bulbs yet ? Some auto stores will come out and put them in for you. I like corfire's suggestion of trying the driver high beam. This will give you a good feel of how it goes together.

First rule, dont touch the glass on the bulb, BRappaport is right about the oils. If in doubt get some rubbing alcohol and paper towel and clean them off.

1 Pull black cap off
2 Wiggle the connector slightly as you pull it off the bulb.
3 Push the metal "spring" in and sideways to release and then flip it out of the way.
4 Pull the bulb out by the prongs the wire connector was plugged into.

Do the reverse to install the bulb.

You asked how do you know it is seated corrected..... if you look at the bulb it has a circular metal flange on it that has a tab. That tab if I remember correctly should point towards the ground. When you put the bulb in just turn it slightly and you should be able to feel the tab catch. That being said sometimes it feels like you got it in right but it is not. You will most likely not notice this till you drive somewhere and you the light beam looks not quite right. To fix just pop of the black cap, release the spring and just reseat the bulb.

Just wait till you decide to get some HID's and have to fish the wires thru that spring. Now thats a challenge!

RowdyRoadster