Hi, the reason for having a positive environment is so that children can be in a place - inside or outside that offers them a variety of opportunities to learn, develop new skills and (if you work in England) eventually reach the early learning goals of the
EYFS (Early Years Foundation Stage)
What development records does your setting keep? If you ask for a copy you'll be able to use the wording that's already being used to write about the features of a good environment and how it supprts development -
personal, social and emotional 
physical,
Communication & Language Literacy Math Art & design Understanding the world
This is a useful book -
enabling environments
Does you setting have a copy you could read? If not there a few preview that may help.
(Please note, where it says about
Every
Child
Matters in the book, you will need to check with your tutor before writing about it, as the book is dated 2015 and ECM isn't always used anymore.)
Creating a positive environment means to take all those features into account and plan a space - one that's welcoming, stimulating, has adults that care, interesting areas and activities. Think about your setting and how they do it xx
Best wishes