Opinion on Big Bangs and Dimensions

i have some qs to clear my doubts about how YA-dwelling scientists (or their readers) view BB (if they accept the theory).

q1
does a BB signify the start of space AND time? or just one without the other?

q2
what is the consensus on how many BBs have happened? is it (the one for our present earth-universe) the latest one or THE one and only?

q3
if BB signify the start of ONLY time, does that mean there was a (uni)verse of 2D before (opposite of behind, before?) ours (humankind in 3D) existed? or still do? like there is a blueprint before (opposite of after, before) a building construction started?

q4
like we 3D creature / being can animate 2D and technically 3D'd 2D, can a 4D being animate or technically 4D'd us?

q5
as 3D creatures have 2D counterparts (like i have my own shadow), is there a 4D me in 4D verse?

i'm sorry my BB qs somehow became ones of the dimensions. but i'd really like to know the answers from you all whose knowledge and wisdom are greater than ignoramus me.

Always both space & time.

This may help dimensionality from this you should be able reason that space must be three dimensional.

This proof is geometrically based so it would hold up for any size sphere you may choose to examine. What is persuasive about this sort of reasoning is that it is no longer based on our senses to perceive extra-dimensions but on what geometry itself is able to bear.

The proof takes the form of a test and is very simple to understand. The test is called The Flatlander's Test for Extra-Dimensions of Space:

Case 1) you would be able to find a curved path from the interior of a circle on a two dimensional (x,y)-plane to the exterior of the circle without crossing the circumference. By solving for z in the Pythagoras Theorem you can easily show that this path’s existed because an extra dimension of space, namely z, was available for its construction.