Troubleshooting CSV Import Issues for Agency List in Slack

Hey everyone - I must have the most basic issue ever but I'm trying to import a list of agencies from a CSV in order to run a search for a specific title. Every time I run 'import' it creates the column but it's blank. At first I had two columns 'Agency' and Website' - when I chose import as tab, it worked but they were imported into one column together. Now I just deleted the second column trying to get the Agency column to import and nothing happens. What am I doing wrong?