Working with loops:

1. Open the sound source you already have

2. select the area you want to be repeated.

3. copy the selected area.

4. Insert it into Multitrack then click on Multitrack button to switch to Multitrack interface.

5.Right click on the selected track and select loop properties.

6. select simple looping (no gaps)

6. Click on the right edge of your sound track and drag it to the right . Here It's been repeated 3 times.