What to consider during an Equity split up?

[Disclaimer: I am very new to all this so pls help me with ur valuable suggestions as I need your guidance] I have an idea which I am thinking to discuss with my friend and I think it can be a good one. So, lets say if it clicks us both. Then how should we plan about the Equity split up. Considering we might have to share our equity in future funding rounds and maybe an employee Esop. Any learning material around it or ur experience will be very valuable for me to start-off.