https://www.brewtoad.com/recipes/simple-mango-pale-ale
Actually used 5 lbs of frozen mango chunks purchased from Whole Foods. I believe Trader Joe's also sells relatively inexpensive frozen mango chunks but my local store was out of stock at the time. I indicated fresh mango in the recipe only because frozen isn't an option.
Added the frozen chunks directly to secondary. No pasteurization or sanitization treatment. The mango chunks caused a stronger secondary fermentation than I expected. Make sure to have a few inches of head room in your secondary vessel. I only kept the beer on the fruit for 10 days. Could have easily taken more but I was impatient.