I have a csv with 2 columns user_id and lead_source.   I went to Catalog and selected CSV under Lookup Tables.  Step 1: I brought in the CSV and Step 2: I mapped the first column (user_id) to User ID (Amplitude User).  It showed me a sample of my CSV and showed both columns at the bottom of Step 2.  I clickd Finish.

I went to data:sources and saw the CSV.  I clicked on the name for ths CSV and it opened to a firm that looked exactly like the form I just completed.  There is a modify rows in step 1 and a download CSV and delete in the upper right, but I’m not seeing anything to edit this CSV and map the second field.  What am I missing?