In reply to Rick Wicklin.

Thank you! I think though that my issue is a bit more complicated: The interaction is between 2 continuous variables:

X = continuous
M (moderator) = continuous
And I want to plot the two lines at +/- sd for both X and M (so I have 4 values for the graph: low-low, low-high, high-low, high-high)

I wasn't sure how to do that and received various error messages.
would appreciate any further guidance,

Thank you!