" The XXXXX is built up by four different main parts with different aim/aims"


- aim or aims?
- is it better to use "consists of" instead of "built up by" ?

//Carl

'built up of' is a bit laboured.

I would recommend:

The XXXXX comprises four different main parts with different aims

(Note: No 'of' with comprises.)

or


The XXXXX consists of four different main parts with different aims

or

...main parts, each with a different aim
...main parts, each with its own different aim