Welcome to the site 
You’ve come to the right place to learn!
There’ve been lots of great resources posted in the resources section of the site, like Jason Keyser’s VFX Apprentice , Gabriel’s Udemy course, not to mention Travis’ monster Getting Started post which links to many things that will be helpful for a beginner.
Feel free to post any work in progress you make in the Personal Work category! Let us know if you have any questions along the way 
edit: just saw you mentioned in your title Unity specifically! Check out @Sirhaian’s post here: Unity VFX Tutorials - Basic
Gabriel’s Udemy course posted above is in Unity as well.