Each alert can have conditions associated with it. The conditions vary depending on the alert type. Some can be very simple, others more complex. It should be simple to figure out what the parameters mean for each alert type.
This is a Moving Up/Down alert. The current quote for AMZN is displayed at the top right below the Symbol and Alert Type selections.
The alert will trigger for AMZN when it moves at least 2 points up or down within the last 5 minutes. The Alert will look at Last to make that determination.
Note that clicking on the Desc button will give you a description of the alert in plain English that may make it easier to understand what it does.
In the Notifications tab you can set how Medved Trader will notify you of the alert once it has triggered.