First, if you're not already, I would op yourself in Console, by running the command op {username}, without the right slash. If you're already opped, you should add the plugins Essentials, and EssentialsSpawn, and you'll be able to do /setspawn, and all under the default rank will have that set as a global spawn point. (Ranks are configurable with luckperms, and make for an easy way to set different spawns for different members of your server.)