This is an old pic, in the meantime I've added some more buttons... 
 
There's a total of 6 sliders, three of them for trim. 
They work, but level flight... still can't get that under control...  
White thing top left is throttle (up-down), the red thingy right behind is for flaps (goes left-right), black one to the right of that is for proppitch. (up-down) 
The red one to its right is the elevator trim. 
Below that, the red one (left-right) is aileron trim, to the left (left-right) is rudder trim. 
(Directions are as-you-view the picture, IRL the throttle and pitch levers rather move fore and aft.) 
The truly amazing thing of this box is that it actually works, and I only have to open it up maybe once a year to fix a loose wire...