Need suggestion about long matrix program

[Amer7]

Thank you road and Raimund for your replies.
I don't understand the code for these "clusters", i just want something simple.
@road
No, I just want to utilize the HP primes stored M1, M2, M3 variables
Why - because from problem to problem the dimensions of the M1,M2,M3 matrix can change.

I want program to utilize M1, M2, M3 - matrices, products of program calculations will be new matrices M4,M5....A1...A7.
And I want to store these in calculator variables because I could view them. ( these will be large matrices with 9 decimal numbers, and print option is awful.
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Can someone just tell me how to make this program.
M1 - Matrix that I input in ( Shift Matrix menu)
M2- Matrix that I input in ( Shift Matrix menu)
//// Program
When I run the program I want it to do Transpose M1*M2*TransposeM1 - And save it in user variable A1

So when the program finishes I press button VARS-USER And i get the matrix A1 with its values.