C# is an object-oriented, strongly and statically typed, programming language. This differs heavily from Lua, which is a dynamic, weakly typed programming language with less restrictions and different coding conventions than C#.
As such, it is recommended to start learning C# from a clear point of view. Below are some good resources to start with.
Microsoft's official documentation and tutorials are a very good starting point for beginners.
SoloLearn has some free C# tutorials. Keep in mind you might see ads on the website.
Codecademy is similar to SoloLearn. It is free for just about all starting courses, but if you want to get into more advanced courses then you will need to purchase Codecademy Pro. The free version, however, will work perfectly fine for just about everyone.
LearnCS.org is a great website to learn. It is completely free, however it is more documentation style like, and there are ads. Overall, it is still a great website when you may need a quick reference for something.
This is a very good video as Mosh does a great job keeping things simple, and straight to the point.
These are just a few resources that are available. Of course, there are many more on the internet, as well as plenty of great YouTube videos. Also there is always Google where you can find other resources to utilize if any of the above don't work for you.