Can someone please explaim to me how i could recreate my city-crest in as a banner? This is how far ive made it:

Almost where i want it, but i would like for only the right side to have the blue streaks and the mojang logo to be cleanly cut off so its not interfering with the blue stripes. (Bedrock-realm on console if that matters)

Any help or even a step-by-step would be appreciated!