How to set Gaaiho as my default PDF reader?

Here are two simple ways to set Gaaiho as your default PDF reader:

1. right-click on any PDF file and select "Properties" > under Open with click "Change..." > select "Gaaiho Doc" or "Gaaiho Reader" > "OK" > "Apply".
2. In the latest Gaaiho PDF Suite or Reader, if your default PDF reader isn't set as Gaaiho, you will receive an alert message when you open the program, select "Yes" to proceed to the instruction window >  click "Continue" and the "Properties" window will be opened and follow the above instruction to complete setup. Click on the upper-right "X" or "Cancel" to continue Gaaiho.
   

Alternatives:

Go to Windows "Settings" > "Apps" > "Default Apps" > scroll down and click "Choose default apps by file type" > find .pdf or other file types that you would like to open with Gaaiho and click "Choose a default" > select "Gaaiho Doc" or "Gaaiho Reader".