Someone wanted to learn this too, so Grasp built them a personal learning path.
You can keep exploring this one or create a path like this one shaped around you.
Recommended resources
Module 2
Regular Expressions and Language Properties
Module 3
Context-Free Languages and Grammars
Module 4
Pushdown Automata and CFL Properties
Module 5
The Turing Machine and the Chomsky Hierarchy
Module 6
Decidability and Undecidability
Module 7
Advanced Computability Theory
Module 8
Time Complexity and the Class P
Module 9
The Class NP and NP-Completeness
Module 10