You need to add it as a NinjaTrader Add-on, below is a video and tutorial to help you.
User Guide
Here is some help on using the product together with a video tutorial on the [NinjaTrader Risk Manager]
https://ninjatrader.com/support/helpGuides/nt8/NT%20HelpGuide%20English.html?using_3rd_party_add-ons.htm
Installing 3rd Party Add-Ons
After you have downloaded 3rd Party Add-On, they can be imported from the NinjaTrader Control Center.
From the Control Center window select the menu Tools > Import> NinjaScript Add-On... to open the "Import" dialog window
- Select the file you want to import
- Press the "Import" button
Once installed, you can access it., from the control panel select new and at the bottom of the list you will see the alarm manager
