The search bar is your friend. When I searched for “sponsors” in the search interface, a top result was this topic: The Guide to Getting Sponsors for your Robotics Team
This isn’t the only topic discussing getting sponsors for VEX Robotics teams, so I recommend checking the Vex forum’s search function out for yourself by clicking on the magnifying-glass symbol in the top-right of the website. Your other questions’ answers can also be found with the search feature, by searching with prompts like, “How to store funds.”
Good luck!