If you want to mix the two pieces, you could do a Crossfade. The gradient mask for audio
- Create a new empty Track
- Copy the part you want
- Paste it in the new Track
- Move this copied part with the timeshifttool from the Toolbox to the place you want and keep it a bit overlapping to the loop in the first Track.
- check the position by playing, to get the rythm right (it’s better to copy a bit more than you need)
- select the overlapping part in the first Track and, menu: -effects- -fade out- or -crossfade out-
- select the overlapping part in the second Track and, menu: -effects- -fade in- or -crossfade in-
If you want more control over the fades, you can use the envelopetool from the Toolbox.
This part would look somewhat like the attached image.
- The last step is to select both tracks and, menu: -tracks- -mix and render-