If I don’t have a pattern, I use graph paper to draw out my project to scale. Count the number of each component, eg. how may triangles of what size, how many rectangles of what size, add your seam allowance to the finished size to get your cut size. Count on 40” width of fabric in a fabric strip cut, then take the size of one component, eg I need 30 -4” squares. If you cut a 4” strip that’s 40” width of fabric and divide it by 4”, you will get 10 - 4” squares out of one strip. So if you need 30 squares you’ll need 3 - 4” strips cut from your width of fabric assuming you want all the same colour (10 squares in one strip, 3 x 10 = 30 squares). Then do the same for all your components.