On the bottom-left section of your main board screen you will find an open chest called an Inventory. It will help you keep your main board organized with relevant items, crates and toolboxes, and give you the opportunity to save the ones you don't currently need, but are valuable to you and may be useful in the future. 

Your inventory is your safe spot. If you feel like you need to expand it, that's also an option! You can always buy more inventory space by using your Diamonds!

Don't forget to check your inventory once in a while to see if you have any relevant item or tool that can be useful as you work to complete orders and progress your studio!