Hi there mmm
Not sure on the specifics of this machine but the in general
descaling - will depend on the quality of water in your location and whether or not you are using a filter
backwashing - with chemical will depend on how many coffees you make each day, i generally do this once a month which equates to about 100 coffees thereabouts. You can use cafetto backwash detergent.
General cleaning should be done on a regular basis to keep the shower screen and group head/handle and portafilter clean.