Your water softener has two tanks and a control head. The brine tank holds salt. The resin tank holds the beads that take hardness out of the water. The control head runs the cycle. Most of the care you can do yourself is on the salt side. The valve, the drain, and the resin are a different job.
What you keep
Keep the salt above the water line in the brine tank at all times. Use the salt type the manual names. Check the level on a schedule you set for your home, and write the date of each refill on the tank.
Break up salt bridges. A hard crust can form over an empty space in the brine. Push a broom handle gently down the center to clear it. Do not stand over the tank while you do it.
Check the drain line. Look at where the brine tank drains and where the drain line empties. Water should flow freely. A soft pool at the drain end is worth a call.
Test the hardness. Use a test strip on the untreated line, then on the treated line. Compare the result with the setting on the control head. If the water tests harder than it should, note the reading before you call.
Keep the clock and settings. Confirm the control head time matches local time. Write down the hardness setting you use. A power outage can reset the clock, so check it after one.
What goes to a pro
Call a licensed plumber for leaks at the fittings, the bypass valve, or the water connections. Water on the floor is not a task to fix by tightening and hoping.
Call a pro for control valve repair or replacement. The valve controls the cycle and the flow. Do not open the valve housing unless the manual tells you to.
Call a pro for resin bed work, including cleaning or replacement that requires opening the resin tank.
Call a licensed electrician if the plug, outlet, or power supply is in question. Check local permit rules before any new circuit is added.
Questions to ask at install
Ask the installer which parts you may service yourself. Ask them to show you the bypass valve position for normal use and for service. Ask where the drain line empties and whether your local code requires an air gap. Ask for the manual and the model number, and keep both with your paper.
Age as a planning input
Write the install date on the paper you keep. Note the age when you plan the next check. When the valve or resin is older, plan the pro visit before the water tests poorly, not after.