Bought Used Game…Want to reset but feel sad about it.

Hey everyone, so I bought this used Mystery Dungeon Explorers of Time, and wanted to play it from the beginning. This previous person has so much progress and I’d hate to erase everything without knowing if there’s anything I can do to preserve any pokemon or start a new save? I’ve never played mystery dungeons on the DS before so please give advice if there’s anything I can do or not haha. Thanks!!!

Hey everyone, so I bought this used Mystery Dungeon Explorers of Time, and wanted to play it from the beginning. This previous person has so much progress and I’d hate to erase everything without knowing if there’s anything I can do to preserve any pokemon or start a new save? I’ve never played mystery dungeons on the DS before so please give advice if there’s anything I can do or not haha. Thanks!!!