If I understood correctly, you found a script for a slot game, and now you want to adapt it to some of your ideas. Adapting and modifying someone else's code is always more difficult than creating your own from scratch.
I'm not sure what kind of help you expect from here, while you have described the problem you are encountering in a very general way.
I didn't "find" a script for a slot game. I paid over 1k for someone to develop it and am having issues with the database or something to this effect. I don't want a site that allows gambling so I want to remove that part and use it as a demo type thing where you get free spins. I would get the original developer to do it but I can't get in contact with them now.
Yes you are right about it being difficult because I have spent over 40 hours messing about with it so far and still can't get it to work so might have to get another one coded from scratch when I can afford it.