I am going to start learning about DFT calculations. Could anyone advise me the best starting point for that? Simple example guiding tutorial with explanations would be great. Any input would be good. Especially, I would want to be able to construct electronic band structures of materials.
There are great suggestions in the other answers, but personnally, I usually advice new comers in my group to read the first few chapters of Marder's Condensed Matter Physics for introduction to condensed matter physics up to chapter 9 treating very quickly DFT, along with this bird's-eye view of DFT.
Electronic Structure: Basic Theory and Practical Methods by Richard M. Martin is a good book. But, it takes time to read completely through it.
In this primer, the first chapter gives a good introduction to DFT. You can probably start with this.
Go to Abinit website and start with the basic tutorials. Also, keep the book by R. M. Martin nearby. The appendices are especially useful for understanding the implementation details of DFT in modern codes.
Computational Physics by Jos Thijssen is also a well written book with computational exercises.
Also take a look at the lectures of Prof. Tomas Arias at https://www.youtube.com/watch?v=oyvGeQ8ehBM&t=3s