Have upgraded from Trial to Enterprise and having trouble with customisation!

Have upgraded from Trial to Enterprise and having trouble with customisation!

In the trial version I had full access to the permissions that allow me to fully customize the content within my leads contacts, fields etc. Now that I have upgraded to enterprise, I have only the ability to create a section and appear to have limited permissions in any other areas.

I'm definitely no techo and would love some guidance here??

Regards Nicole