First, after importing the recording file, click the multi-channel button to switch to the multi-channel editing mode, and then drag the recording file to the right channel 1 with the mouse. Only files added to a track can be edited.

Just increase the volume of the 1 track. You can drag the white button under the track 1 to adjust the volume up and down, and increase the volume up, and vice versa. Or enter parameter values below. When you drag the button to adjust the volume, the following parameters will change accordingly.