Carefully copy your new tiles and paste them over the old ones.
Over the years, the ROM hacking community has developed powerful tools that make tile editing more accessible than ever. Here are the modern essentials for Fire Red tileset hacking. pokemon fire red tilesets
You do not have to draw everything from scratch. The ROM hacking community has created incredible free-to-use resources. When using public tilesets, always check the creator's terms and provide proper credit in your project documentation. Excellent communities to search include: Carefully copy your new tiles and paste them