[Custom campaigns] How to make a custom icons in custom campaigns?

Good day to everyone who worked with custom campaigns. I’m in process of making campaign and I have want to create a special icon for missions. I understand, how to include it in game. But how does you make them? Where? And how you divide them for 3 elements. It would be great to understand.

@Ongarelli173 @NekyChoi @cly0806 . You’re the first who I remembered. You worked with custom Icons. So, I hope, you can help me. Please!

read my english tutorial about json on steam you will find the answer,if you have any question,email or reply below here and i will respond when i have time.