The Ramchal’s Derech Hashem is a must read classic for any Jew.
I’ve created a one page table of contents of Derech Hashem, which you can download here.
There are two translations available from Feldheim:
Rabbi Aryeh Kaplan’s translation can be purchased from Feldheim or Amazon.
Rabbi Abba Zvi Naiman’s translation and elucidation can be purchased from Feldheim or Amazon.
They’re both excellent and highly recommended to purchase and read over and over again to understand the fundamentals of Judaism.