hope you don’t mind if I answer this publicly, as I’ve gotten a few questions about this already haha. the RAM editor is an online application found here. you have to extract your save file from your game (explained on the site), and the RAM editor edits that file. you can spawn items, move buildings/ pwp’s, change a villager with a new one, etc. if you see screenshots of towns with bamboo and pwp’s in rivers or on the beach (or anywhere the game doesn’t allow them to be), someone has used the RAM editor to do that. descrossing‘s RAM editor guide provides more thorough information! :) xo
edit: as it says on the RAM editor’s site, your 3ds/ xl/ 2ds must be at 9.x up to 9.5.0-22 (9.5.0-23 or higher are not supported).