I've been interested in making my own add-ins for my Casio FX-CG50 calculator however I can't find any tutorials, documentation or just instructions for doing simple stuff like drawing a sprite. The only thing I can find/see people pointing towards is this: https://prizm.cemetech.net/Prizm_Programming_Portal/ and using the PrizmSDK with C or basic C++. However even some code copy-pasted directly has errors running and some pages (notably Popup_windows, Advances_GUIs & Drawing_Sprites) lead to 404s. So are there any other good tutorials, programming frameworks or just a way to get all the commands I can use?

(Sorry if I haven't used the proper programming terms for anything, hopefully it gets my point across)

As far as I know, the Prizm wiki is the most complete repository of Prizm C/C++ documentation around. It looks like that set of tutorials isn't (was never?) finished: note the "Article creation is still being completed." above it. But we're here if you have any specific questions, and you might have to ask or dig around in the source code of released programs (https://www.cemetech.net/downloads/browse/prizm) and in header files to find what you need.

Kerm is right, there aren't many good Prizm tutorials around, but the Prizm wiki has some pretty decent documentation.

For example, you mentioned drawing a sprite. Here's a simple routine to do so on the Prizm: https://prizm.cemetech.net/Useful_Routines/CopySprite/.
The wiki also has documentation for most of the Prizm's useful syscalls, under the Syscalls category: https://prizm.cemetech.net/Syscalls/, and some other useful routines: https://prizm.cemetech.net/Useful_Routines/.

Let us know if you have further questions!

The libfxcg examples will probably be useful to you as well, demonstrating some of the basics.

Sorry for the late reply! I've been very busy the last couple days. Thanks for the help, I thought that other than the page I linked to, the rest of the wiki was just about coding in Assembly (or whatever that language is you can use directly on the calculator) for some reason. I'll have a look at some of the tutorials to help make to basic stuff (thx dr-carlos) and look through the examples and just other people's programs to hopefully get some further info (thx KermMartain & Tari)!