You'll add the random number and a different constant for each row you make. The random number generated will be between 0 and 1, so, for the first row you'll need to add zero; add one for the second row, etc. Try making nested loops and see what you get. Do you understand how rows & columns of a 2D array are generated in this fashion? Are you familiar with the For loop's "i" and "N" terminals?
Show me your code, Wireworker, and I'll show you mine.