Knowledge base for helpdesk

Hi, Leading a project for my helpdesk, I need to create a wordpress knowledge base who will contains troubleshooting articles. (PDF files for the most). First, we have to type a login and password to access the site.(Only IT members must have access to the knowledge base). This wp site will be on an internal network on the company. The home page must contains a search barr (who will be able to browse among titles of posted articles), a manageable area with recent articles and another area with some important articles that I can pin on homepage. It also be great if I can put a name or a nice picture as top banner to be more esthetic and pleasant. Herewith 2 captures of old WP themes who could be taken as examples of my need. Don't hesitate to reach me. Jérome.