Well I was going to try and make a tutorial but there are just WAY too many steps! I wouldn't be able to fit all of them on here! But I will give you a few pointers!
First you should cut your entire sheet of Plastic canvas into 3"x2 7/8" squares. (This step is optional. But it's a big help when you actually start to cut out the snowflake.)

I don't have a pattern to go by...you're just gonna have to count out the squares. (Make sure you're holding the square the right way! 3" across and 2 7/8" down)
Make sure to cut out two. On the 2nd one you cut out the middle. BTW, it helps to have a pointy pair of scissors!


You start here. Make sure to keep some yarn out. This is how you keep it together without knots!

This is where you will start around the edges. Remember to always bring your needle through from the back.

You will go back later and cover the rest of the canvas.

No knots! Slide your needle through the yarn on the BACK of the snowflake.

After you finished all four corners. You'll move to the middle. You'll start it out the same way as the beginning of the snowflake.

This is what the middle of the other snowflake should look like when you are done. Again make sure to keep some extra yarn out and wrap around it so there are no knots!

Sorry I couldn't put a WHOLE tutorial on here. I hope this helps some! Feel free to ask questions!