Downgrade from 5S to 4

Hi,

I wanna switch from 5s to an old 4 (not S) - but harving problems transfering the data.

Could You help me? I need a step-by-step dummy.

I'm well aware that some apps won't work in the old phone - but I only want to save contacts, calender and massages.

I have made a copy at iCloud (and on my PC), but was not able to save massages. How do I do this?