Enabling the Data Pack on a New World
Because Cobblemon City Towns is packaged as a single merged data pack rather than a standard mod file, Minecraft loads it per world unless your modpack uses a global loader. When setting up a fresh survival world for your Cobblemon journey, open the world creation screen and click the Data Packs button. Move the Cobblemon City Towns file from the available column on the left into the selected column on the right, then click Done before generating the world. This ensures the updated settlements can spawn right away around your starting region.
Adding Towns to an Existing Save
If you already have an active Cobblemon world, exit to the singleplayer menu, select your world, and click Edit, then Open World Folder. Open the datapacks folder inside and place the single Cobblemon City Towns file there. Rejoin your world and run /reload if commands are allowed, or close and reopen the save to apply the change. Because Minecraft only places structures when generating terrain for the first time, towns will not appear in areas you have already explored. Travel outward into unvisited chunks to encounter the newly enabled settlements.