there are two aproaches to painting cammo:
1 paint the lightest shade first, the theory being that it is easier to paint dark colours over light ones, rather than the other way around. This is a good idea, as light sandy colours do not cover dark browns or green very well.
2 . Work out what the predominant colour is and start with that. This will give the figure the over all appearance of having this colour as the main one in the Uniform. This method is also quite good if your pattern has large areas of green and brown, but only small areas of lighter sand colours. To start with light sand on say a modern Woodland or DPM pattern tends to leave the impression of a sand yellow uniform with green and brown patterns on it, no matter how hard you try to paint over most of the sand.
For Fallschirmjager splinter pattern, I'd start with the lighter sandy colour, and them do the brown and green splinters.