Seeing that now, and this may be simply a misunderstanding. No need to reinstall.
Load the first file (6:00). Click the Edit menu, then the INSERT FILE toolbar icon at end and load the second file (10:00).
Timeline now shows about 16:00.
Make a selection by dragging the center of the red cursor from approximately 5:55 to 6:05. The selection area will change color...
Click the image to enlarge
Go to the Effects menu and click the Fade toolbar icon. Click on Crossfade Selection. The result should look something like this.
Adjust the white squares to taste.
Click the Crossfade button.
Another method...
Load the first file. Click the Effects menu, the click the caret to the right of the Fade toolbar icon.
Choose Crossfade to Clip and End for the position.
In the Crossfade box, choose Open Settings and set the end time to 5:58 or so. It should look something like this...

Click the Crossfade button, then OK. Result is 16:00.