The videos you uploaded aren't in the best position (see the sticky), so we can only see so much. Also, the weights are super light, so if there are issues that crop up with heavier weight we won't be seeing them here.
SQ: Ribs down/tight abs when you take your breaths so that your back isn't arched. As you lean over at your hips, let your knees move forward at the same time (hips and knees together).
BP: Begin each rep with elbows leading forward (not out to the sides). This might be enough to give you vertical forearms in the bottom. If not, widen your grip a finger to achieve it.
DL: Again, the video is not making feedback easy. But your hips are too high in the setup. Drop them so your knees are flush with the front of your arms. Also keep your head down - don't crane it up as you lift.