Aajurroomiyyah is a basic Arabic Grammar book that students usually study as a beginner.
There are many different explanations for it. I've posted a few to help you.
Four audio lectures by Hasan Somali (Arabic/English)
http://germantownmasjid.com/explanation-of-ajrumiyah-sh-ibn-%CA%BFuthaymin-ustadh-hassan-somali/
Powerpoint/Video
http://germantownmasjid.com/supplementary-slides-for-ajrumiyyah-class/
Aajurroomiyyah Arabic/English Text Click here
Aajurroomiyyah in chart form (Arabic only but the introduction and background to the author is in English): Click here
Aajurroomiyyah Arabic Explanation of Shaykh Muhammad Saalih al 'Uthaymeen Click here.
