Firstly replace parts as required.
This information will set the needle to the hook correctly. The next task may need to be checked and adjusted if required will be the feed timing and is covered in another FAQ
Retiming the hook to needle setting.
Using a brand new needle in the machine, turn hand wheel anticlockwise until the needle moves to its lowest point - then back up 2.2mm
Turn pre-loosened hook gears or belt pulleys by hand (in the same direction as the machine would run), watch the hook movement as the hook point rotates behind needle point - when the hook point is directly behind the needle tighten all gears etc.
Some disassembly may be required so you can view the hook point. eg. needle plate or spool case