The insertion depth is the distance from the top edge of the bed frame to the support surface for the slatted frame. The insertion depth is indicated on all our beds - on many models it can even be individually adjusted during assembly. If you subtract the insertion depth from the total height of your mattress and slatted frame, you will know how far the mattress protrudes from the bed frame.
The less it protrudes, the more discreet and straightforward the bed looks. The more it protrudes, the higher the sitting and lying surface will be - this can be more comfortable.
A good guideline: the mattress should sink about halfway into the frame. With platform beds, it lies almost flush with the frame without slipping.