M = your two-row matrix
M1 = M(1,:); % 1st row of M
M2 = M(2,:); % 2nd row of M
However, in many cases it is better to simply use M(1,:) and M(2,:) directly in your downstream code instead of creating separate variables M1 and M2. This is particularly true if you have many rows to work with ... you should never create a bunch of variables called M1, M2, M3, M4, etc for that situation.
