I need to associate a meta description in my wordpress website for google listings

I am looking to insert a meta description into a wordpress website www.east7.co.uk. My developer has moved to australia so I can't ask him to do it.

I have wordpress login etc.

See attached screenshot of how the meta description appears currently in google.

I need to amend so that it simply appears as “East 7” and shows a blurb of the text from the home page – i.e. East 7 is the voice of housing in the East of England.
We are an informal alliance of nine of the largest developing housing associations based across the East of England’s six counties. Our members are Aldwyck Housing Group, bpha, Circle, Cross Keys Homes, Estuary Housing Association, Flagship Housing, Grand Union, Hightown Praetorian & Churches Housing Association, and North Hertfordshire Homes.