Click on Appearance -> Customize from the main menu. When the customize screen loads click on Background Image to expand the background options and select or upload your new background. You can specify the background repeat (horizontally, vertically, tile, or no repeat), background position (left, center, right), background attachment (fixed or scroll), and background color.
Once logged into wordpress, click on add new under the FAQ menu to add a new question and answer. Enter the question in the top line and enter the answer in the wordpress editor. You click Add New from the FAQ menu every time you want to add a new question/answer. When your ready to display the FAQ on a page simply use the shortcode [faq]
Responsive design means the website will automatically adjust it's layout and resize elements to fit the device that it's being viewed with. For example if you load this website on a mobile device it will be the same design but the layout will change to fit the device. To see a live example of this resize your browser window now and watch the responsive design in action. If you have a mobile device scan the QR code to load this website.
To display information in the sidebar for the model page you are working on just wrap the content with the shortcode tags [sidebar]your conent here[/sidebar] and everything between the two [sidebar_content] tags will be displayed in the sidebar for that page only.
You can display a photo of each model on the page that links their personal profile page with this shortcode: [display-posts post_type="custom_type" image_size="thumbnail"]
. To use it just copy the entire (highlighted) code and paste it where you want to display the models.