u/Broad_Regret_6130

I’m interested in learning how to build decks and I’m wondering if there are basic rules of thumb that might help me more easily reason about the sizes and spans of joists and beams. For example, are there simple mental math formulas for approximating how large/tall a joist should be based on its span or how large/how many boards a beam requires based relevant factors? Any little tips, tricks or mental models would be appreciated