Learn Arusian Grammar Step-by-Step
You can find all the contents for each level (from A1-C2) for learning Arusian to live in Arusia in this website. They are divided by levels (with ALPT-E being the lowest and ALPT-A being the highest) and contents in one level depend on contents from the previous level. Knowing that, you shouldn't advance unless you are sure you mastered all the grammar topics in a specific level. Although Arusian grammar itself isn't difficult, it differs a lot from English and it will require some practice to get used to.
You can access the content by clicking on the level you want on the sidebar or by downloading this ebook.