How do I get rid of the BOOKMARKS section along the left side of my screen?

In the upper left hand corner of your iPad screen, to the left of the address bar, you will see a “blue” icon that looks like a book. Tap this icon and the sidebar should go away.

Tap the book icon to the immediate left of the address bar.

For more about Safari, visit > Bookmark favorite webpages in Safari on iPad - Apple Support