Vacancies for all ESA departments and information about careers are published only on the ESA portal website.
The current list of vacancies is listed here.

The ARTES website does not give access to the documentation of specific Invitations to Tender (ITT's). To download Statement of Works, Contracts or Tender Conditions as well as Clarifications, you need to open the specific ITT on EMITS, ESA's Electronic Mail Invitation to Tender.