I want to build a device that has a fairly large hdd that i can watch movies and shows on as i walk home, similar to an ipad or tablet, but with a larger hard drive. I chose this because it seems like something i can use in my everyday life and to be run by arduino or raspberry Pi or similar . But sadly i lack the knowledge and funding to do so.

I just got a job and will start working in a few weeks which solves one problem.

I dont know where to start on projects like this.

Any recommendations or lists of components i would need would be greatly appreciated