How to participate in the development ?

[CDJimmy]

Hi,
I'm developper for a while, and i never colaborate on a public project.
I use cobe in my website (and it's work well), but I want to try to update your lib for adding more interactions.
For exemple the possibility of choose color for each markers individually (witch is a feature you ask for #20).
Or adding mouse events on markers...
So I want to participate on this project and propose my pullrequest if I sucess to adding these features lol.

My question is, how can I run your project ?
I cloned it locally and I try to run server with npm but I got errors and I'm not sure if I did it correctly.
Your readme explain how to use your lib but not how to run https://cobe-playground.vercel.app/ in dev env locally.

I'm kind of: "hey, how could you improve the project if you're not able to run it ?".
As a non english I alway stayed away from dev comunity, but I want to change that.

Could you help me ?