I am looking to create my own code/model for modeling electromagnetic problems via Finite Element Method and Finite Difference Time Domain method. I have been reading through the literature and textbooks but there is an abundance of information. I am looking to see if anyone has any recommendations on resources for getting started with this endeavor. I know what method I develop is heavily dependent on what I want to do at the end, but I suppose I am looking to stay general for now.
It seems like "Computational Electromagnetics for RF and Microwave Engineering" by Davidson (2011) is a good source and Wikipedia has information. If anyone else has any information, please let me know. Thank you in advance.