Help Setting Up Shop

So I'm trying to build me a shop but I really don't know how you do the sign and chest thing so people can left click and buy an item.. Can someone help me?

Player Shops

(Watch Page)

Player Shops

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  Any player can create a shop in Town - shops can't be created in the Wilderness or Nether Worlds. All players can buy from all shops, too.
  
  
  
  Contents
  
  • Buying from shops
  • Selling to shops
  • Setting up your own shops
  
  
  Buying from shops(top)
  
  
  You buy from a shop by left clicking on the shop sign. Here is an example of a shop sign that allows you to only buy from it:
  
  
  
  This shop lets you buy 15 Dragon Eggs for 100 Rupees.
  
  
  
  Selling to shops(top)
  
  You can also sell to some shops, if the owner allows it (you can't sell to the official Empire Shop). To sell to a shop, right click the shop sign. Here is an example of a shop sign that only allows you to sell to it (and not buy):
  
  
  
  This shop lets you sell 5 potatoes for 100 Rupees.
  
  
  Some shops allow you to buy and sell from the same sign. Simply click the mouse button for the action you'd like to do while looking at the sign. They look like this:
  
  
  This shop lets you buy 20 saddles for 1000 Rupees, and sell 20 saddles to it for 500 Rupees.
  
  
  Setting up your own shops(top)
  
  
  Shops can only be created in a residence in Town. Creating a shop lets you sell items to other players forRupees. You create a shop by placing a sign with special values next to a chest with items you want to sell. When you place the sign you need to put the following values on each line:
  
  
  • Line 1 - Empty (blank, it will auto fill with your name later)
  • Line 2 - The quantity (example: 10)
  • Line 3 - The cost (example: 30) - for sell prices, use :cost (example: :30)
  • Line 4 - The item name (example: Gold Block)
  Here is an example of setting up a shop to sell 10 gold blocks for 30 Rupees:
  
  
  
  
  
  Once you click done on the sign editor the shop system will take care of the rest. You will also want to put as much of that item as you want to sell into the chest, don't forget to stock your shop often!
  
  Note: You can put the word "FREE" as the buy or sell price to

Thanks so much!!!!

Also, you were supposed to read the wiki...