Hi Tom!
First of all, thank you for your interest in Origami!
I’ve created a fresh installation for you here: http://www.satoristudio.net/origami-demo. The login is “origami” and the password is “demo”.
Videos can be inserted into posts either by using the native WordPress functionality or by using the theme’s [media] shortcode. Please see an example on the first page of the theme demo, the bottom-most post. Please note that Origami’s styling retains 16px borders on both sides of content, so if you wish the video to stretch the entire length, you will need to add the following line to the “style.css” file (by going to “Appearance – Editor” in the admin):
.post-wrapper .post-content iframe { max-width: 656px !important; margin: -16px 0 0 -16px !important; }
You can view the full-width image on the full-width page in the demo.
Regarding your last question: the header can contain either an image (example), an image slider, a recent post slider, a Google map, or a custom piece of HTML code. In theme settings, you can choose the default state (e.g. image) and on each particular page you can choose the header type for that page (i.e. if you do not change the per-post setting, the header will default to an image, otherwise it will display the type you’ve chosen for that particular page). Origami does not support individual header images for each page – however, you can use the featured image functionality to set a featured image for each post or page separately, as it is done on most of pages and posts in the demo (e.g. here).
Hope I’ve managed to clarify things for you :) If you have more questions, do not hesitate to ask!
Sincerely,
Andrew | Satori