You could start with the Unity Learn site, which is free. There is a C# Survival Guide that might be a good place to start. You can also just use Google to search as there are more Unity tutorials out there than can be counted.
The C# yellow book is really good. It's free and written by a professor with many years experience in teaching programming. http://www.csharpcourse.com/
Unity uses C#, which is a very popular programming language not unique to Unity. There's an enormous number of resources for learning the language.
Have you tried any courses on Udemy? Or how about just looking on youtube. There's thousands upon thousands of tutorials on there with how to code and work within unity.