Qim at this point I say stop. And go read and learn css. Good starter site is http://www.w3schools.com/cssref/default.asp
concentrate on css3.
Why? All your questions are because you do not know css.
Where do I do that? in the css or in the actual html field?
It makes no difference as long as you do it.
below the image where there is a title "Registration Page" the vertical amount of space has increased and I would like to bring it
back to what it was.
Don't know where it was but added to css this
might give you a starting point.
All your html elements are there. You now have to style them with css.
Oh the text is the wrong size....Style it.
The text in the third line is the wrong color....Style it.
See what I'm getting at?
Good luck in your studies.