Dishwasher/Spülmaschinen tips

I am new to the developed world. Do you have any tips about maintaining the Spülmaschinen (Dishwasher) in Germany? :)

• how much salt should we put in the water hole at the bottom? how often?

• how frequently should we use the dishwasher? we use it only 4-5 times a week to save electricity bill. Is that good practice?

• what are some good brands from Rewe or DM to buy for dishwasher? Or any other brands?

• what else should we buy for dishwasher? tablets? gels? liquids?

• any other tips?

Herzlichen Dank im Voraus for your kindness and help.