Your project might not have aspx files since it might be another kind of web project.
However, if it has a ClientApp folder:
- go to the standard view of the Solution Explorer (Ctrl+Alt+L) where you can find your-project name solution (click on the folders icon at the top to be sure (saying "Solutions and Folders"))
- right-click on the ClientApp folder itself
- Browse with... will show up near the top (near View in Browser option), click on it and the browsers dialog shows up
- click on your preferred browser
- click on Set as Default
- click on Browse to confirm (this will open the browser you just chose on that folder)