IMPORTANT: On NetBeans 9, use only version 188.8.131.52 or above. Using any previous version of this plugin on NetBeans 9 will cause severe IDE-wide indexing slowdown. Download the latest netbeanstypescript.nbm file from the Releases page. Then, in NetBeans, go to Tools > Plugins, and select the "Downloaded" tab. Click "Add Plugins..." and locate the netbeanstypescript.nbm file. The TypeScript Editor should appear in the list. Select it and click "Install".