cc 2014 importing psd questions

Still getting used to CC, I need to know how I go about the following.

I have 20 psd's

I'm able to import the first which populate layers in the FIRST frame of my timeline.

need to know how I can import the rest of the psd's so the second will appear on frame 2, the third on frame 3 etc.

When I try to do this anything after the first psd populates the first frame and just adds layers, follow?

any help?

R