i like the format of your very short tutorials!
i only watched at the videos without the sound and this is my feedback.
lot of feedback : - )
generally:
- it's scribus 1.5.5, not 15.5
- hide all the toolbars but the "tools" one. put the tools toolbar on the left side of the scribus window
- make sure that the content you're showing is nice!
- most of the time, have the properties palette (and/or the content palette) docked to the right of the window (or the left, if you prefer)
scribus looks much better this way:

i make a list of things i noticed while looking at your videos. there are reasons for each of them, but -- to keep it short -- i do not explain them... for each of them feel free not to follow my hints or to ask for explanations if somethings looks bizarre.
images tutorial:
- do not use the context menu for loading the image. there are better ways to do it:
- the file menu (the standard place)
- ctrl-i (the fast way)
- double click on the empty image frame (also fast)
- drag and drop from a file manager or an image viewer
- do not use copyrighted / trademarked images and logos in your tutorials (only use images that are cc-by; mention the sources.)
- use an image that has a big enough resolution for the size of the frame (avoid the dpi warning in the lower right corner of the frame)
- trigger the "adjust frame" to image after showing it
- add a quick introduction to the free scale / scale to frame in the image tab of the properties palette (content palette in 1.5.6svn)
preview tutorial:
- use the menus and ctrl-alt-p, not the toolbar (the goal is to have the button back in the status bar at some time...)
paragraph styles:
- do not use blue text
- put nice formatted text: the first frame is ok, but it should not be bold, blue and right aligned. and it should not overflow.
- dock the text palette to the right
- do not apply the centered text to the default paragraph style: only show formatting that looks good!
- if you show the paragraph effects, apply at least one of them (and warn the user that they are experimental)
- in the character style, don't apply bold to a long text; if you increase the font height, also increase the line spacing.
- red on 10% cyan is a terrible choice. on green it's even worse
- if you show the font features, you should explain what they are for.
master pages
- do not put random text frames with random sizes on the page. and no text outside of the margins : - )
- do not put "title" on the MP. the user cannot change it.
- in the header, do not write "en-tête", but a real header (something like "introduction"): again, it's not editable and we should say this from minute 1...
- do not apply the MP from the context menu but from the page menu
voilà, i hope that the remarks will help you create even better tutorials in the future!
ciao
a.l.e