Congratulation!!!
Read the assembly instructions, look at all the pictures, spread out the parts. Then.. read the instructions again!
Now put the darn thing together properly.
Go ahead, ask me how I know. LOL
Next, PROPERLY THREAD THE MACHINE.
Do not change any settings or tensions. If it does not sew correctly, it is probably operator error. It was sewing fine when it was packed for shipping.
Another point is to sew without leather or material. Sound weird, right?
Use paper or light cardboard and just the needle, no thread. Learn to make corners, go the speed you want and don't waste good leather. Cut a strip and practice your edges, like it was a belt.
Practice, practice and practice.
Good luck,
Kevin