Then select Edit, Define Pattern, from the menu.
For this tutorial the overall scarf design will be 6300 pixels by 6300 pixels, which, at the 150dpi we will choose, will be 105cm by 105cm. Do you want a border on your scarf? What size border do you want? Bearing in mind that the edge of the scarf will be rolled, so some of the edge will be lost in that way, we will set a border that is 200 pixels wide on each edge. For this reason we will start with an image that is 5900 pixels by 5900 pixels.
Make sure the layers window is open (If it isn't then select Window, Layers from the menu). At the bottom of the layers window is a half black half white circle with a small triangular arrow pointing down.
Click the half black half white circle and select Pattern from the menu that pops up. Your image will be filled with the most recently used pattern. Click on the triangular arrow next to the pattern image, and select the pattern you want to use from your pattern library. Use the scale slider to scale your pattern up and down in size until you find the size you want to use. Then click OK. You will be returned to your image which will now be filled with your pattern.
First you need to mark the current area in some way, because when you increase the size of your canvas your pattern will fill it automatically.
So, in your layers menu, click on the background layer, and then use the paint bucket to fill the whole of that layer with a different colour (any colour that is not the default background colour - I am going to choose black to do this, while my default background colour is set to white).
Then select Image, Canvas Size from the menu. Set the width of the canvas and the height of the canvas each to be 6300 pixels. Click OK. You will see that your image now has a differently coloured border.
Now you need to rearrange the order of your layers. So, in the Layers Window, if your background layer is locked (has a little lock symbol by it) double click that layer, then click OK. This will unlock the layer so that you can move it.
Then, in the Layers Window, click and hold the background layer, and drag it up above the pattern layer.
Now use the magic wand to select the inner part of your image, the portion that you coloured before increasing the canvas size (the portion that I coloured black). Then press delete.
You should now see that your image has a patterned inner area and a plain coloured border.
You can use the paint bucket to fill the plain border with a different colour, or a different pattern fill. I have filled my white border with the same pattern repeat from my pattern library, using the paint bucket this time. There is no scale option with the paint bucket so the pattern comes out at a smaller size, which is what I want.
Finally, save your image file, and come along to upload your file, and that's it. We'll print it out for you.