There are 3 ways to change this:
1st way
You need to right-click on the desired file
open the settings
by using the button «Change» to change the default program.
2nd way
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.
3rd way
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.