Advance Map ROM hack

[Haydos04]

Hello everyone, so I am EXTREMELY BRAND NEW to rom hacking. I've learnt a FEW basics like warping and map design. I have no idea yet how to script but ill figure it out. So my plan for the rom is for the player to start in their house and walk downstairs to then find their mum is getting robbed by team rocket. Having no pokemon u look for oak on route 1, he takes u to the lab and gives u a pokemon. The rival follows u home to help with team rocket. This initiates a double battle. Does anyone have ANY IDEA on how to implement this and these events? Thanks in advance.