empty out beans as much as you can with your hand. Use a vacuum cleaner to get the rest; Refill with fresh beans.
Remove the automatic brew mechanism from the side door and wash it in the sink by hand. Run your fingers over the filters in the brew mechanism. Refit.
remove the drip tray assembly empty and clean both grind dregs and water.
Switch the machine on. Wait for it to go through its initialisation and if all is well it will come to some kind of "Ready" stage.
Open the steam tap and allow the machine to draw new water from the reservoir, and flush it through the steam boiler and out the steam pipe.
Make a coffee selection and run out no less than three black coffees, to run any old remaining grinds through and out.
If it needs a descale it will come up on the screen as such. Only you can decide if you want to descale if the computer doesnt prompt you to do one.
Get hold of an owner booklet, read and digest.
If you must do a descale, DO NOT USE Common CITRIC ACID....go to a specialist esp machine store and buy an approved descsaler for use for the type of machine.
After all that if there are no error messages, proceed to work out the grind / dose adjustment compromise to get best possible brew from the beans in use. I would set the dose to say 3/4 on the scale, and set the grind accordingly after that.
Hope that helps.