User manuals for Astrodevice products have been prepared in PDF format. To read them, you can use free software such as Adobe Acrobat Reader.
For the convenience of viewing live content and to ensure fast download speeds, the user manual files are stored in Dropbox cloud. When you click a link with a user manual file, you will be redirected to an external service, where the content of the manual should show up. There will also be a download button on the page: when you click on it, you will be able to fetch the file to your drive. You do not need to create a Dropbox account to view or download the user manual files.