Someone did a really bad job at chronicling this series so here it goes.
The first 4 issues of the ongoing Army of Darkness vol.1 are named Army of Darkness vs Re-Animator #4, after issue 5, it becomes Army of Darkness.
This first volume lasts until issue 13, after which Ash's crossover with the Marvel Zombies begins.
After the crossover, Ash get's an own new series, Army of Darkness vol.2 (although the index on this page says "Army of Darkness: from the Ashes/The Long Road Home).
Volume 2 is the longest running series.
It starts with a new issue 1 and lasts until issue 27. However, on this page, someone started putting the Army of Darkness volume 2 comics on this page from issue 14 and on.
So what you see on this page are Army of Darkness Vol.1 issue 5-13 and Army of Darkness Vol. 2 issue 14-27. For Army of Darkness vol.2 issues 1-13, click here.