I need help with changing the size of the slider

How do I change size of the slider

Here is my site Read-Only: LINK
(how to share your site Read-Only link)

Can you provide a bit more information on how you want to resize it along with a read-only link to your project? There are lots of ways you can change the size of a slider and it will really depend on the site context and which direction(s) you need it changed.