In your Square account, ensure that your items and sales order history are up to date.
It helps if your inventory is tracked with current stock levels set, and pricing data up to date.

In StockTrim navigate to Load Data and select Square

You will be then navigated to Square to login with your Square credentials

You will be then asked to approve StockTrim accessing data from Square. Click Allow and then they sync will begin

On the dashboard you will see how many products you are overstocked or understocked with, as well as the related costs. Click, 'See my plan' to see the optimal reorder points and suggested order quantities to save you these costs.

On each product, you can select the 'i' icon to bring up the demand analysis. See your trends, and see how the forecasts are calculated so you can oversee the results to have confidence they're correct.

Click the settings wheel to set the lead time and service level. Make sure that the lead time is set so that you have enough stock to cover the time between when you place the orders with your suppliers and when they arrive.