Assuming you would like a step-by-step guide on how to thread a Juki dx7:
1. Before threading the machine, make sure that the presser foot is in the raised position and that there is no lint or debris around the needle area.
2. To start, raise the needle to its highest position by turning the handwheel towards you. With your left hand, hold onto the end of the thread coming from the spool. Then use your right hand to take hold of the tail of thread near the needle and pull it towards the back of the machine. This will give you some slack to work with.
3. Next, insert your threaded needle into one of the lower tension discs (the ones closest to where your hands are). Make sure that you are holding onto both ends of thread while doing this; if not, your stitch will be loose and incorrect.
4. Once the threaded needle is through one lower tension disc, bring it up and out through one of upper tension discs (there should be two). Again, hold onto both ends of thread while doing this step so as not to create a loose stitch.
5. Finally, pass your threaded needle down through The Take Up Lever guide hole (this is located just above where your right hand is positioned). Doing this correctly will cause The Take Up Lever to rise automatically; if it does not rise, gently push it up with your finger until it locks into place.