Based on the existing timeline, you can set the model's keyframe after selecting the model from the list or scene.

After determining the position of the model in the scene and timeline respectively, click Add Keyframe to fix the state of the model on the timeline.

After determining the second keyframe position on the timeline, the model will be automatically keyframed after adjusting the model position or size and other states. The movement rate of the model in the keyframe will be calculated automatically according to the time difference between the model's position in the scene and the timeline. If you need to adjust the model's keyframe to overlap the playhead and keyframe position, you can update the model's position, size and other parameter information in the current keyframe.

Select a keyframe to move its position on the timeline or press Delete to delete an unwanted keyframe.

Keyframe "left" and "right" control, quick switch between "previous keyframe" and "next keyframe". 

Light switch: After selecting a light source, you can add a light keyframe anywhere on the timeline.

Rate matching: After selecting a character or vehicle model, turn on the matching switch to match the model's own movement rate (e.g. character step rate, wheel speed) with the keyframe movement rate.

Use the mouse wheel to move the timeline and Alt + mouse wheel to zoom in/out of the timeline.