Make sure you are logged in - see 'Sign in' at the very bottom of the page (light blue so hard to see)
Edit a page by hitting 'e', save with CTRL-s or Save/Opslaan in top right corner
All commands are also available through the menu, toolbar, and advanced operations through the 'settings' style icon on the top right.
Create a new page by using 'c'. Except for your general personal portfolio info, put all other content in subpages under your portfolio page. If you create it in the wrong place you can move it with shift m.
For more options see the top right menu (if you are not in edit mode).
We only have 100MB in total, this fills up quick!
Convert pictures to smaller sizes so that these dont take up hundreds of KBs or more; use VIMEO or other video sites for video; put large attachments elsewhere and link to it from the site; dont distribute binaries with source code etc.
You need a google account to access but you dont need a google email address if you dont trust the 'dont be evil' mission statement long term
Here you can read how to embed Vimeo videos. But basically you can include rich content by clicking the <HTML> button and inserting any 'embedding' HTML code. Youtube videos can be directly inserted using the Insert menu. So dont just put links to media, always try to embed/display on the page directly