How do you use player shops? Answered here.
Quick Note - If you'd prefer to see this format in-game or you don't need full explanations, just type /quickshop or /quickshop help and it'll send you a list of the commands in chat. Also, keep in mind for every /quickshop [command] command there is, you can substitue /quickshop for just /qs.
Business Major 101 (Shop Creation) - When going to create a chest shop, using /quickshop create [price] while holding the item you want to sell in your hand and pointing your cursor at a placed chest will turn it into a chest shop for selling. Use /quickshop price [newprice] to alter the price of an existing chest shop with your cursor pointed at it. If you'd like to change the item, use /quickshop item and hold the new item in your hand while pointing your cursor at an existing chest shop. To change it into a buy shop, simply type /quickshop buy and it will then turn the shop into one where people sell the item to you. To turn it back into - or newly into - a sell shop where you sell the item to them, type /quickshop sell. Both of these require your cursor pointed at the chest. Lastly, to remove a quickshop, look at it and type /quickshop remove.
Restocking and Emptying - To restock or empty your chest shop without opening it, use the /quickshop refill [amount] command to refill it from your inventory and use the /quickshop empty command to put all of the items inside it into your inventory. (The sign may not instantly update, but punching it once will fix it!)
Employees? - You can also add staff members to a chest shop. To set a staff member for a chest shop to allow them to refill it as well, you would use /quickshop staff add [username]. To remove them, the command is /quickshop staff del [username] but if you'd like to remove ALL staff, it is /quickshop staff clear. If you want to see all your staff on one shop, use /quickshop staff list.
Selling the Business (How to Transfer Shops) - Finally, you can also transfer ownership if you'd like to give your shop up to someone else. When looking at the chest shop, type /quickshop setowner [username] and it will transfer that specific shop to the new owner. If you want to transfer an entire STORE to someone, or ALL of your chest shops, type /quickshop transfer [username]. The new owner will get all of the items in the chests upon transfer, so be sure to empty them prior if you want to keep anything.