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If you don't have any ArcGIS for Desktop software
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And you'll receive a full copy of ArcGIS for Desktop at the Advanced license level and selected ArcGIS extensions at no cost for 60 days.
If you have a single use license of ArcGIS for Desktop
Go to Start All Programs ArcGIS ArcGIS Administrator. Make sure you have the appropriate Desktop Single Use product selected, click Authorize Now, and follow the instructions. Click Register Single Use and Extensions and follow the instructions.
After installation, go to ArcMap Customize Extensions. Check the box next to the extension name.
If you have a concurrent use license of ArcGIS for Desktop
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