The sewing machine in the clip you've linked to is going very slowly; it seems as though you have no familiarity with machine sewing, have chosen to jump in without knowledge or training, and are uncomfortable with the machine. You also mention not knowing how to thread the machine or perform the most basic function of it.
There is no way to slow a basic machine beyond pressing gently on the foot pedal; some higher-end machines will have a stitch speed regulator, but these do not drop the speed any further than the clip in the linked video. What needs to be addressed is your own comfort level.
Return to the place where you purchased the machine and, instead of asking about speed, ask about classes. Many places will offer them, and frequently they'll be free if you've purchased a machine from them. Even if they don't offer them, they'll know where to direct you to take a class and learn how to use your machine. Due to your lack of experience, you have no confidence or comfort around the machine, are confused about how it works, and don't know where to start; an in-person class is the best way to handle this extreme lack of comfort. They'll be able to show you how to thread your particular machine and help you directly to get over your fear of it; after a good class, you should be able to easily sew simpler items confidently, with no fear of the "speed and noise" of your machine.