How to use reverb?

Go to the mixer panel by pressing on the 3 vertical faders icon in the top right of the sequencer window, and press the ‘Reverb’ button to activate reverb for one of the 4 tracks. When reverb is activated, the button will be red:
You can then choose the reverb algorithm you would like to use on the selected track by clicking on the room setting. You can then adjust the reverb amount using the Dry-Wet horizontal slider.