If you have not downloaded the installer file yet, use the instructions on this page to get the current version or a previous version:
https://support.sighthound.com/staff/kb/articles/154
After you download the Sighthound Video installer file, use the Finder to locate the file.
Double click on the installer file named SighthoundVideo.dmg
A Finder window now appears with 3 items in it (you might not see the .url and .app)
Applications - shortcut to your Applications folder
Sighthound Video Documentation.url - Link to online documents
Sighthound Video.app - This is the application we are installing
Drag "Sighthound Video.app" to the "Applications" shortcut to install it on your hard drive.
If you already have it installed, you will now see a dialog indicating that it already exists.
It is asking if you want to replace it with this new one.
Go ahead and click on the "Replace" button.
If Sighthound Video is running, you will get a warning saying that it is in use.
Click "OK" and Quit Sighthound Video, so you can try that drag to Applications again.
You will get a dialog about the file copy that will disappear after a few seconds.
Close the Sighthound Video installer window.
Click the red dot in the top left corner of the window.
At this point, you should start Sighthound Video.
You can find it in your "Applications" folder or in Launchpad or in your Dock.
To start Sighthound Video the first time after installing, you might need to right-click it and select "Open"
Or, it might work to Double click on the Sighthound Video dog icon to start it.
Since you just downloaded it, there may be a confirmation window the first time.
Click on the "Open" button to continue.
It is now going to complete the installation, and needs access to your system to do it.
A Dialog "SighthoundVideoLauncher wants to make changes" appears.
Enter the password that you use on this computer and press "OK" to continue.
Sighthound Video should now be running.
Select the menu item "Sighthound Video => About Sighthound Video"
This opens the "About Sighthound Video window, where you can verify the version.