To check your connections to ensure that the correct data is being pulled into Inventory Planner. Go to Account > Settings to see which sales channels are connected. 

Next, check Connections & Warehouses to see which are enabled.

Once enabled, you'll see each warehouse in the Replenishment section of Inventory Planner and other reports.

Note that billing in Inventory Planner is based partially on the number connections or enabled warehouses, whichever is greater. Your first connection or enabled warehouse is included in the base price. Additional enabled warehouses will increase the price. See billing details here.

You can view billing for your account by going to Account > Billing.