This is a project you are doing for your mum...I'm not sure whether it is supposed to be a learning experience for you or your mum just wants it.
Making such code for such a project is easy. But using scripts from other places and customizing them - terrible Idea. SQL is easy, just take a day and leanr how to use PHP and MySQL. If you still decide to use scripts from others, you will hit a brickwall because you don't understand the code well, the code is not speciifc fo that problem.
But off course ofr things such as Image Uploads, you can use other people's scripts as they are tried and tested in security and such but constructing the project from the ground up on borrowed code - bad idea.
Whatever small knowledge you have, use that and start expanding on that. If you reach a module you have no idea how to make, ask here and we will give you ideas and guide you on what to do.
Just my 2 cents worth.