There are 3 ways to change this:
You need to right-click on the desired file
open the settings
by using the button «Change» to change the default program.
You need to open the control panel on your computer
select Programs -> Default Programs
select "Associate a file type or protocol with a program"
Then you need to find the right file extension, and select via the button "Change program" to change the program.
If you want to open the file directly via another program and set this program as the default program, you need to right-click on the file – «Open with» - and select the program, then the file will be opened immediately in the selected program and this program will install by default.
If you have any additional questions, please contact Customer Support of UNETA.