If you want to loosen the tension you have to go into tools and make the adjustment there. Having the correct setting for the fabric will most likely solve the tension problems. I run a very thin, narrow ribbon thru the tension discs every once in awhile whenever I use different weights of thread or especially if you use a thread that creates alot of lint. Also when you change thread clip it close to the spool then pull it out from the needle- you don't want to pull lint back up into the machine. Invest in the mini vacuum that is sold for machines to really get rid of all the lint in the machine. you've spent alot of money on your machine a few more $$ on a little aid to keep your machine free of lint is a great investment. The A foot and the B foot are very similar to each other BUT when the stitch calls for an A foot you Can use the B Foot. When the stitch calls for a B foot you shouldn't use the A foot. You MIGHT not get the same results. If you are having problems with the feed dogs eating the fabric(sinking below the stitch plate) I would advise you to use a straight stitch plate. It has a single hole to prevent the fabric from being forced below the stitch plate. When using such a plate you have to remember that the needle cannot be moved at all-it must remain in the center position. When you want to wind a bobbin from the needle you must have a metal foot in place and set the presser foot in the highest position. the thread needs to feed from under the foot.Do not wind the bobbin at a high speed because the friction creates heat and will actually warp the bobbin and it won't come off the spindle. You will then have to pull off all the thread that is on the bobbin remove it and throw it away- it will never be the same again.