Can someone give me a full guide of the grenade quest?

[Platinum Pirate]

Well, the quest has been simplified. It's so easy your thump thump breaks for the longer and more challenging version. You still need to get to Notoriety 20 to unlock that quest as you know. Once you talk to Captain Jack Sparrow, you'll see good ol' Ewan [where's my Kraken] McKraken who needs you to sink ships and some land enemies. The challenging part is searching for the materials at Kingshead. You still need a friend or two with you throughout the island. Then off to Fort Dundee in Padres.

Maybe someone can give you a step-by-step guide as requested. I'll gladly meet you in-game if you like me to help you there complete the quest.