Tannlang

i have had my 880 for 5 years- it has been used for the last 4 years. I have just taken 4 days of classes- trying to make piece with the it. but luck. my Bernina dealer offered by $2000 for a machine that has not been used. does anyone have any ideas., you tubes, etc on threading the machine for embroidery- everyone at the store where i bought it threads it differently- then tell me i an doing it all wrong. i am so frustrated to have spent over $12,000 plus a $1000 upgrade to plus- and a machine i can not even use. i really would like to get a 790- i bought a 700 to do my embroidery