We require a modification to existing Sencillo theme for Wordpress.
The changes are:
1) For Portfolio post type, add 2 fields: Authors and Illustrators. These should be either a select/autocomplete input box to allow selecting multiple authors/illustrators.
2) For Staff post type, the post view should display a list of all Portfolio post types which the staff is related to (see 1.)
3) For Staff post type, a page which displays a list of all related Portfolio. This should have a similar filtering like the Portfolio post.
The Sencillo theme will be provided to you. You will then need to upload, change and test this on your own Wordpress instance.
After my receipt of the modified theme and tested on our own environment (we will do that ourselves), we will then release payment.
Straightforward and simple.