There are descriptions but you can only see them when you are editing your classes. Its faintly written in the top right corner. Some genius decided to make the text the same colour as the background.
The whole menu system isnt very well plotted in my opinion. There are too many sub menus, text is sometimes hard to read and there are just a lot of bad choices like having players and chat on different menus in the pre-game lobby.
As for your progress being reset its a known bug and very common occurance. Later on you will be losing ranks, challenges, dog tags, etc. Thats when it
really gets annoying.