Tap the Split Screen button in the main menu. It's a mode — turning it on switches Dual Camera off, and vice versa.

Tap Choose Video. The picker has three tabs: Swings — reference clips you've already imported, saved with their impact marks; Photo Library — any lesson or model video on your iPad; My Practice — your own recordings (favorites are starred; for a dual-camera swing pick Main or Second Camera). Anything you import from the Photo Library is copied into the Swings folder automatically, so next time it's one tap away. Reference videos must be 15 seconds or less — trim longer clips in Photos first. Still images and Live Photos work too. If your Photo Library videos don't appear, the app needs permission to access your photos: open Settings → Privacy & Security → Photos → LVProDSM and choose Full Access (with Limited Access, only the photos you selected will show).

When a reference loads, the Impact Sync bar opens with a red I caret on the timeline. The app listens for the strike and places the caret there (or two-thirds in if it can't hear one). Drag the caret, or use the frame buttons, until the frame shows the club on the ball, then close the bar. The mark saves with the clip in Swings, so it never needs marking again. Reopen it any time with the ↔ I button.

The reference loops seamlessly while you practice. Set its speed to 0.2×, 0.5×, 0.75×, or 1.0× and match the model's positions with your own — the live mirror shows you both at once. Mute or unmute the reference with the speaker button.