All beans are different, so you could start by buying a bag of beans from a cafe you like. You need to get your grind setting spot on, small differences in the grind will make a big difference in flavour. Expect to go through at least a bag of beans testing until you get it right. The wrong grind setting will easily ruin even a great roast. A different brand of bean may then still need a change in grind setting.
Given your machine has an integrated grinder, don't keep the hopper full of beans as they won't like heating up and cooling down all the time. Think of beans like a lettuce - buy fresh and use soon. Plenty of good bean subscriptions out there; I have one out of Melbourne from a cafe called St. Ali. Or buy and support local. Don't use supermarket beans. Don't buy beans if there isn't a roast date on the bag.
Learn how to pack the coffee and tamp it down neatly. If this isn't done right the water can rip the puck to pieces and make an awful coffee.
Learn to froth the milk properly. Plenty of videos online about this, but if you're hearing a lot of bubbling and spluttering you're doing it wrong. Keep frothing until the jug is just too hot to touch then stop. Consistency should look a bit like paint for a flat white.
Some people like measuring things with scales. I just got there by trial and error, depends how invested you are in learning.
Be prepared to make quite a few shit coffees until you get the hang of it.
Heaps of videos online to devour, I don't mind James Hoffmann: