Plug in the softener. Most have a digital display that asks for your water hardness level (you can get a test strip from a hardware store). Enter the number, set the time, and start a manual regeneration cycle. This flushes out any air and gets the resin ready.
While it’s running, check all your connections for leaks. Run your finger under each joint. If you feel even a tiny drip, tighten it a smidge. A little drip today is a puddle tomorrow.