How would I make my arms have the same height as my cursor?

I am extremely bad at math and CFraming, how would I make my arms have the same height as my cursor?

Screenshot_2
On this image, the arms should be a little more upwards,

Screenshot_3
and on this image, the arms should be a little downwards.

I’ve seen countless of games do this, I would also like to keep the animations played, so how would I do this?

I saw an answer to a similar post where someone was trying to script something similar
https://devforum.roblox.com/t/how-could-i-make-your-arms-and-head-follow-your-mouse-up-and-down/397227/5?u=sippinonjuicebox
If that isn’t your solution then there are many other posts in that thread that could help.
Good luck!