Complex Turret Tutorial
Defend your homes or towns with turrets. We have three types of turrets which are Burst turrets, Siege Turrets, and Slowness Turrets. You cannot craft these turrets but you can buy them in our admin shop.
You have to buy the correct ammunition for each turret in the shop. 
3.Click the Turret option which is the chest button. You can enable the options for attacking. If you want to attack players,monsters,animals and others you can enable or disable this. 
- Burst Turret needs Burst ammo
- Siege Turret needs Siege ammo
- Slowness Turret needs Slowness ammo
How to make the turret work?
1. Place your turret in your desired location.
2. Right Click the turret. You will see the GUI.
Emerald button- click if you want to upgrade but remember it costs money to upgrade this.
Chest button- This is for turret options.
Redstone- click this to destroy the turret. Remove ammo before clicking this button.
Whitelist players or your friends so that the turret will not shoot them. Click the paper button to add a player to your Turret Player Whitelist. To remove the player, right click the player head.
4. The dispenser button is the Ammunition Storage. Click it and place your ammo on the slots.
5. Click the arrow button to go back to Turret options. Click the custom head at the upper right. This will enable or disable your turret. Enable it. Then it should be working. Make sure you have ammo.
DO NOT BUY A LOT OF TURRETS. Default players can only place 4 turrets.
Credits to the dev of this plugin
https://www.spigotmc.org/resources/complexturrets-defend-yourself-using-turrets-1-8-1-19.92756/