Script Installation and Minor Function Fix

I'm looking for an expert to help with installing a script and fixing a minor function. The specifics of the script and the function will be shared upon selection.

I need script installed on my domain from github

I need login issues fixed (currently after signing up you can login on 1 device for 1 session only)

I need the very simple referral system fixed (it was working but think its linked to login issue)

This project is built with .
Vite
TypeScript
React
shadcn-ui
Tailwind CSS

I can share project url, github code and hosting/domain for installation