This information is probably listed elsewhere, but I did not find it. I think this info would be more valuable to those people who are just starting the game, and did not play in the beta. Hence, the "For Dummies" because I have been feeling like a dummie until I learned this basic stuff about Bridge Officers, also known as BOs.
1. Buying a Bridge Officer in the Exchange (Auction Hall)
For those who don't know, the Exchange Section is in the Earth Spacedock. Just keep running around the hub until you find it. You access the terminals for the Exchange, the Bank and the Mail there.
So let's say you want to buy a "better" BO of any type than one you have right now.
So you open up one of the Exchange terminals in the normal way, by accepting the invitatiion on your screen, "Access Exchange." Easy so far.
On the left is a list of what "Items" are for sale. Select the Bridge Officer section. Notice above the "Items" section is a place to select "Rank" and "Quality." So far I have only seen Ensign ranks on the BOs you can buy, so you can leave that blank. But the quality level you pick for your BO will affect what abilities and skills it comes with. The higher the quality, the more Superior abilities it will have.
How do I read the list of abilities: A Bridge Officer has a list of 12 abilities or skills. The first four on the top are the Space Abilities. These can be trained at the Bridge Officer Trainer (located in the Personnel Section) for a lot less than it costs to buy a new BO. The next eight are the Ground Abilities. The last four Ground Abilities can also be trained at the Bridge Officer Trainer. What that leaves us with is the first four Ground Abilites.
These cannot be trained! As far as I know (and I am only a dummie), this is one of only three reasons to buy a new BO. The other two are choosing the sex and the race.
That is why you will see a great diversity of the prices for BOs on the exchange.
Now that you know what you are looking for and at, I would suggest selecting "Rare" for Quality. Very Rare will be something you pick when you have lots of credits. But you can sometimes find a good deal under Rare.
So you have selected Rare Quality, pressed the Search button on the upper left, and wait...then you see a list a mile long. You may want to narrow it down by putting in some qualifiers in the Search box. Let's say you put in Vulcan Engineer, and press search again.
So start looking through those lists. Some of the Superior Qualities you will find are Superior Mind Meld, Superior Covert, Superior Nerve Pinch, and others. These will cost you more than the Basic ones.
Then we come to the sex of the BO. I have heard people lamenting that they can't get female BOs on the exchange. Not true. You just have to learn what names are female before you buy them. All the Vulcan females I have seen listed with a name like "T'(rest of name)" are females, like T'Pol from Star Trek Enterprise.
Once you buy your new BO, you have the option of changing the name and the way it looks. Change the name first, or you will lose the option for that.
I guess I covered what I know here. Oh yes, here are the prices to train a BO, by rank of the skill.
Ensign, 75 credits
Lieutenant, 150 credits
Lieutenant Commander, 225 credits
Commander, 300 credits
I suggest only training a skill for the current rank of the BO. You may find out more about how to choose what you want later from someone who knows more about this than I do.

I'm just a dummie trying to have fun. I welcome all corrections, suggestions, and additional information on this subject.
See you ingame,
Hamadryad Long
USS Humpty Dumpty