Just got a reef angel but there is no instructions in the box-
could someone guide me what to do ?

Download the manuals on the reefangel.com website

This link can be found through the "Download" button just below the search in the top right and get to the "Manuals" tab. . You should start with "User Manual v2.1.5". If you ordered additional accessories, you will want to get related documents. Sorry, just learned that I cannot post links including those of this site but ask if otherwise stuck.