How do I import actions on a Mac

I'm having trouble with the actueal importing of the script. When I click IMPORT it doesn't show my file as selectable. I tried RTF and TXT. I'm also on a Mac. I tried to find other import helps but yours is like the 4th one I tried and all the others didn't have what I need. Thanks

See e.g. here:

It's available via the Import... menu item available from the Add button + of the actions window. It allows for importing actions from the Windows version that use the .mta file extension.