RPG Isometric game

I'm working on a mobile Rpg game for the game engine Corona SDK, it uses the Lua programming language. I need help with a simple inventory system think like Fallout 1, Dialogue tree or dialogues options, and enemy combat system with pathfinding. Im using the Million Tile engine and isometric tiles. I need this to be clear commented so a beginner like me can add on to it later say for example add my own items or weapons or character strengths.I dont want to make this complex like a dungeons and dragons game with crafting I just want this to be like a simpler version of Fallout 1 and be able to add my own story and art later after you help me with the initial examples. Requirements are experience with Lua, Corona sdk, English must be your first language communication is important.