For a modeling portfoilo am I allowed to?

Take photos using a Nikon d5100 camera? And also am I allowed to wear for example sea folly bathers in a shoot I I get a friend to do it?

Added (1). An I able to take photos without a proper photographer?

I think you can wear anything you and/or shoot director says.

Use anything. But you can't make a portfolio on your own. You need a Management company to sign you of saying that you are good to work with.