Make large container carrying eggs, principally (6)
I believe the answer is:
Here is my best explanation:
'make' is the definition.
('create' can be a synonym of 'make')
'large container carrying eggs principally' is the wordplay.
'large container' becomes 'crate'.
'carrying' indicates putting letters inside.
'principally' says to take the initial letters.
The first letter of 'eggs' is 'e'.
'crate' placed around 'e' is 'CREATE'.