If you have not already done so, insert a grid into your display. How?
If you have not already done so, add the data source. How?
On the Columns tab, select the column you want to set thresholds for.
On the Threshold tab, clear the Use Default Column Settings check box and select the Enable Threshold check box.
Click the Load button. The Load Threshold Table dialog box appears.
Select the threshold table you want to load and click Open.