Did you buy a new machine or used? For new machines, they all come with manuals or if you google your brand and model, there’s probably something online that shows you. If you bought a used machine, I highly recommend taking it into a sewing machine repair shop and having it serviced. Here they’re re-oil the machine and make sure that all the parts are working. it usually costs under $100 for this service but the bonus is that they’ll show you how to thread your machine. If you’re phone can do video, record it so you can give yourself a refresher course if you need it. 🙂