In Lesson 2 | Uṣūl Al-Sittah, you mentioned bid'ah in the usul and furu'. Can you please explain the difference between usul and furu' and bid'ah in them.

Bidʿah in the uṣūl is innovation in the foundations themselves, like the bid'ah of the Khawārij and the Murjiʾah. As for innovated practice in the furūʿ (the branches), usually have to do with innovated acts of worship or that which is linked to it. Such questions are long and better asked for the Friday live qna.