How Do I Tell If It's Working?
• Do /datapack list in game. Does the datapack appear green in that list? If not, it is not installed correctly - follow /faq Server Installation in the Discord.
• If the first step was successful, type /locate biome #terralith:all_terralith_biomes (/locatebiome #terralith:all_terralith_biomes for 1.18.2 and lower) in game and see if you get a result. Replace terralith with whatever relevant datapack you're installing. If you did not get any results, follow the Server Installation mentioned before.
• If you're using Structory, do /locate structure structory: (/locate structory: in 1.18.2 and below) and follow the previous steps.
• For Continents, there isn't a sure way to tell. Just make sure you followed the Server installation FAQ, see if the land looks like continents, and use something like DynMap if you'd like to see if it's working.