Hello Kathy,
I think you want to read this answer from Walter: https://uk.mathworks.com/matlabcentral/answers/79885-reading-dat-files-into-matlab which explains how to do it.
Then plotting should be straightforward. I would save the output data as variables, XY, then take a look at "doc plot", called by writing it in the worksapce.
Remember that Matlab works in order of row then column so if you wanted to plot the 6th row against all columns you would write plot(X(6,:)); or similar, depending on how your data was arranged as variables.
Hope that helps. Give it a try and see how you get on.
10B.
