i thought "boleh" also means "can"/"may" https://dictionary.cambridge.org/dictionary/indonesian-english/boleh
You can find all rules about Indonesian in Tata bahasa. But that is not one book that you can buy somewhere. It is in my study books at every chapter. You can use an Indonesian dictionary (kamus). But than the Indonesian version for Indonesians. Like a Longman in English. "Kamus besar bahasa Indonesia".