Yo @karistouf,
Did you check this section of the Gray Book?
https://thegraybook.vvvv.org/reference/getting-started/beta/introduction-for-vvvv-beta-users.html
On the left-side menu, you have dedicated pages for various topics such as User Interface, Document Structure, etc. Some screenshots are still missing here, but that could already shed light on some beta/gamma differences.
And since you were asking about spreads, you could check this video :
The vvvvTv Youtube channel has a bunch of specific HowTo videos such as this one.
There’s also this video by @chk that covers spreads (also check the whole playlist) :
Just found out @Takuma also made a video on the topic :
And to finish, there’s also this vvvvery old series of tutorials by @joreg, and most notably these “spreads vs spreading” videos that I remember finding quite helpful at the time. Gamma was not a thing back then, so it shows VL used inside vvvv beta, but the rationale would still apply.
Now to answer your questions
If you type “mean” in the node browser, you should see a node called “Average”, which does exactly that :
I think it would help if you created individual topics for those very specific questions. If you struggle with that, there’s a high change that other users would do as well, and having very specific topics helps massively when searching for information.
In VL, Sequence is basically a generic name for “a collection”. A Spread is a certain type of sequence, same for Dictionary.
Nodes that you will find in the Sequence category can apply to any “collection”. But nodes in the Spread category will only work on spreads.
If you’re looking for help on that topic, check the Collection section of the help browser. You should fine quite a bunch of useful stuff in there.
Hope this helps.