Indonesian doesn't has any "to be" like in English. So, "Dia kuat" literally means "He strong", Subject and Adjective.
Remember, "dia" can be meant "he/she", so don't be confused.
Are there tenses in Indonesian? Does this work for past, present, and future?
There are no tenses in Indonesian. If you want to add an expression of time, just add the adverbs of time (yesterday, today, tomorrow)