Say you are interested in finding some ancestors that you know were in a pioneer company traveling west. Click on the "Find LDS Ancestors" link and this is what you will see...
Look under "Search Pioneer Companies." When you click on the link, it will ask you for the name you are searching. You can also search by company if you know this or the year involved. This is what I found for my William Gimbert Saunders...
Now I can read about this ancestor. Also note under the sources that there is a link to read a trail excerpt. Cool, huh!
There is so much more to this desktop that all I can say is GO PLAY WITH IT! Maybe you will be able to knock down a brick wall with specific sources listed that you didn't know about or that you didn't know how to access!. Isn't the Internet wonderful?