When you first get your sewing machine, it can seem a bit intimidating. There are lots of components and it's not always obvious what everything does.
For you to get the most out of your sewing experience, it's important that you 'make friends' with your sewing machine. The more you understand what it does and how it does it, the more successful you will be in using it.
It's completely normal for you to be cautious about messing with the settings. You may feel that if you mess it up, you'll never be able to get it working right again. This couldn't be further from the truth. The more you mess with it, the easier it will be to adjust it again.
If you have a less expensive machine, this becomes even more important. As machines get more expensive, they get more automated and handle adjustments themselves, to some degree. However, it's still very important that you are able to fine tune to get great results.
You want to be able to use any machine to its fullest potential. That means that you should be confident setting it up for sewing any type of fabric. If you’re sewing jeans or home dec, you'll need heavier thread and a larger needle with the appropriate tension for both. You may want to switch to sewing chiffon and that will be an entirely different setup.
If you understand what everything on the machine does, making this switch will be a breeze and no matter what the fabric, you'll be very pleased with the results.
You should definitely read your manual thoroughly before you begin. However, I would suggest that you label your machine, too. If you don't have a label maker, just write on some pieces of tape or even use a pencil directly on the machine. You can take the reminders off, when you're more comfortable with how the machine works.
From a practical standpoint, we all have limited time to allot to our sewing, so don't waste it digging out the manual every time you want to sew or getting frustrated because you turned the wrong dial.