Go into the FX button an press it. On the screen you will notice rev or chorus or delay. Use the interval button or the hold button to move you from revb ,chours or delay. Once you have the reverb spot stop pressing on the button. Then use the hold or interval button to increase or decrease the amount of reverb.
Hit the reverb but then use the top or bottom levers on the side. I run between 60 an 70 on most reverb settings. On my you tube chanel I belive I show how to set reverb . Hope this helps.