When you buy a new piece of equipment, read the damn manual. I don’t care if you’ve run virtually identical pieces of equipment for your entire life. Read the damn manual.
And if you DON’T read the manual, and the piece of equipment won’t work, read the damn manual THEN.
And if you STILL haven’t read the damn manual, don’t call the store screaming about how we sold you defective merchandise, because I WILL wait you out and then walk you through the steps to start your new lawnmower properly and be delighted when you clearly feel stupid.
The fact that I sound about 14 over the phone helps with this, but still, you could avoid the whole thing by just reading your damn manual.