How do I fix the bottom screen?

My Nintendo DS Lite has been through a lot. I got the Mario Red Limited Edition version when it came out, and since then, the top screen is missing, but the bottom screen still works, so it has the functionality of a GBA. The screen is white with black dots on it, but if I plug earbuds into it, I can hear the game running. The external speakers do not work, but that’s not an issue for me. It has been in this state for many years, and I’ve been wanting to fix it for a long time. How do I repair the bottom screen? I am 18 with little to none tech repair experience. Thank you so much for the help?