Step 1: Download and install the MolecularShell VPK by following this tutorial here. https://www.youtube.com/watch?v=bQEPnRMP5cg&t=4s
Step 2: Download FileZilla client and install the DMG on your MAC
Step 3: Once installed, Open the FileZilla client and you will see the Host at the top left. Open MolecularShell on your Vita and hit SELECT to enable the FTP Client. Punch in the ftp://XXX/XXX/X/X:XXX to your host on your FileZilla and select Connect. The ux0:/ is the root directory of your memory stick on your vita.