If you'd rather watch, start with episode 2. The anime only lasted through volume 13, chapter 8, And still skipped a few chapters towards the end.
If you'd rather read...
Volume 4 chapters 1&2 are his backstory, then from where the anime starts. Volume 13, chapter 8 is where the anime ends. The "Two years later" timeskip is (partially) the first three volumes, then continue from there-present.
Yes I just looked through the manga to find all that.