How to keep assets from being added to Sequencer?

I am going absolutely insane with this. Every week I need to make use of UE for a new project and each time I end up with the same problem.

I’ve got a scene and when adding or moving meshes around. I see it reflected in the Sequencer.

Items which I do not want in there and which end up screwing around with my changes.

What am I missing here? Please, help.

thanks