Hi and welcome to the Forum.
I owned a Sunbeam for several years and it was a great machine - I used the sunbeam tablets to descale and clean mine. There are several products on the market available from the site sponsors. You may want to talk to them to see the alternatives to the sunbeam tablets which are a little expensive. I use Caffetto clean for the weekly clean of the brew head and I also use it to clean the group handle with my new machine and it should work OK for the cleaning cycle on the Sunbeam (only use a 1/4 of a spoon).
I used the descale tablets from Sunbeam and they worked well for the three years I had the Sunbeam (6910) but I am sure one of the sponsors will have a product that is cheaper.