I understand you can add onto the end of a list like this

Code:

However, how can I do that with a matrix? I already have all the values in another row of a matrix that I'm trying to copy over to a new row

[F]{3,1,1,3,5,5,.1,4},{3,2,1,1,3,1,0,8},{3,3,1,3,7,7,.25,2},{3,4,1,5,3,.02,6},{3,5,7,10,6,1,.15,1}
I want to Copy Row X of [F] over to [C] but Row X is added onto the end of [C]

You can transpose the source matrix and then use matr>list() to get the Xth row of your matrix into a list, then you can transpose the destination matrix and use augment() to add the newly made list to the last column of and re-transpose it so that the columns become rows again.
I think the following code should do the trick (note that you need an extra matrix variable to store the intermediate matrix to because List►matr needs to put the matrix somewhere)

Code:

If you know the dimensions of the matrices beforehand, you could also do it with seq() which would be faster because all of these matrix commands are pretty slow.