I have two data sets(floating point numbers) which I want to combine

One data set is 11 branches of N = 100 and the other data set is 4 branches of N = 100

What I want to do is add the numbers together in all combinations so I have 11 branches with 4 branches each with N = 100 data points.

I’ve tried various combinations of simplify, graft and flip matrix but i’m not getting what I want.

Can anyone point me in the right direction for this?

Thanks