To begin with Pooja had a Group of objects (flags for Vistied) hidden via the timeline (as a/the Group). But when it was time to hide the again (so they could show later, via an action), she UNhide'd them in the timeline, selected the Group('s) layer and went up and clicked the eyeball to the left of Groups name, at the top of the Properties panel.)
My question is. If you need to start your slide with hidden stuff (that you are going to SHOW later via an action. Does it make a difference if it is hidden via the timeline vs. hidden via the Properties panel?