New. Slider speed and buttons?

This is my website
I added 4 things 3 images + 1 youtube video under the section “what’s new?”

  1. I need them to be a bit fast, but i cant seem to find the way to do so.
  2. is it possible to add a slider? like buttons on the sides?
  3. have the same size? the youtube thing looks very bad cause of the black borders.

Please advice.

Here is my public share link: LINK
(how to access public share link)