1. Go to .minecraft\resourcepacks\[​The pack you want to edit]\assets\minecraft\mcpatcher\ctm\[​The block you want to edit].

2.



Make 46 different png files with the patterns shown in the picture above, rename them with their respective numbers according to the picture (e.g.: 0.png) and use them as a base.

3. Now edit those 46 images like this:

--> -->

4. Create a text file, open it with Windows Notepad and write:

matchBlocks=[​The numerical ID of the block you want these textures to work with]
method=ctm
tiles=0-46

(Here is a website with every block ID: https://minecraft-ids.grahamedgecombe.com/)

5. Save the text file. After you close it, rename it to [​The block's name].properties

That's pretty much it. My English isn't that great so I know I may have spelt something wrong or have not made something clear, so feel free to ask any questions.

Thanks :D