If you want to draft your own knitting pattern, there are a few things you need to know. First, you'll need to decide what kind of garment or item you want to knit. Once you have a basic idea, you'll need to sketch out your design and calculate the dimensions of the finished product. To do this, you'll need to know some basic math and have a good understanding of how knitting works.
Once you have your sketch and dimensions, it's time to start drafting your pattern. This is where things can get a bit tricky, but there are some helpful resources available online and in books that can walk you through the process step-by-step. In general, though, you'll start by creating a gauge swatch so that you can determine how many stitches and rows per inch your knitting will have. With that information in hand, you can then start mapping out your pattern on graph paper or in a design program like Photoshop.
It's important to remember that when drafting a knitting pattern, simplicity is key. The more complex the design, the harder it will be to follow (and knit!) your pattern later on. So take your time, make sure everything is clear and legible, and don't be afraid to ask for help if needed - there's no shame in admitting that this isn't an easy task!