Updated: 06 December 2021

That you are reading this article is a good starting point in itself!

So where can you go to find out information about Sage X3 ?  It depends on what you are looking for of course...

Knowledgebase
Knowledgebase (KB) articles tend to be fairly short and deal with one specific issue or problem/solution.  

Navigate to https://kb.sage.com/ then select the "Sage X3" option
This has many years of Sage X3 KB articles, I'm sure some of which you have already come across.  

Blogs
Blog articles tend to be  more informal and perhaps lengthier articles, often aimed at explaining how something works and/or could be more encompassing and higher level than a KB article.   We welcome any feedback you may have via the comments.  You are reading a blog article now, so have obviously found it!

This is the UKI blog location (https://www.sagecity.com/gb/sage-x3-uk/b/sage-x3-uk-support-insights) 

There is also a blog contributed to by the US support team, so may also be worth a look as well! (https://www.sagecity.com/support_communities/sage_erp_x3/b/sageerp_x3_product_support_blog)

How-To videos

If you go to the UKI home page at https://www.sagecity.com/gb/sage-x3-uk/ you will notice a "Videos" tab which takes you to our YouTube channel

Announcements of new products, new patches, alerts and general news
The Sage X3 UKI Support team posts this kind of information to the snappily titled Sage City forum "Sage X3 UK Announcements, News and Alerts" forum (https://www.sagecity.com/gb/sage-x3-uk/f/sage-x3-uk-announcements-news-and-alerts)
Hopefully you already subscribe to this forum, as there is lots of useful and sometimes even critical information being fed out from here

*NEW* There is a "Sage X3 Content Newsletter" that will be updated each release, that gives all sorts of useful information and references to other helpful links.  You can find it in the normal Online Help in the "Whats new" section, but can also access it directly at https://online-help.sageerpx3.com/erp/12/wp-static-content/news/en_US/newsletter/Content-Newsletter.htm

You can also take a look at the latest Sage X3 Release notes which are also found in the "Whats new" tab in the online help, or directly from https://online-help.sageerpx3.com/erp/12/wp-static-content/news/en_US/ReleaseNote/RELNOTE_V12.0.28.htm

X3 Online help
Sometimes it is easy to forget about the Online help!    This can now be accessed directly, the more experienced people will remember Sage used to only allow access via X3 itself, but this restriction has been lifted

The online help consists not only of the "official" help text for everything... but also has tutorial videos under the "Tutorials" tab and also it's own "Knowledgebase" articles under the "Knowledgebase" tab

The help text is version specific, so access URL should include the version you are after:
http://online-help.sageerpx3.com/erp/12/
http://online-help.sageerpx3.com/erp/11/
http://online-help.sageerpx3.com/erp/9/

Technical Help

There is a seperate section of the online help for "Technical Help" located at http://online-help.sageerpx3.com/erp/12/public/index.html   There are various guides, such as how to delete folders, Sizing your Syracuse server configuration, setting up OAuth2, as well as things like the system prerequisites

Latest patches
Sage Support maintain a list of latest patches in the Sage City articles linked from Sage X3 Latest Patches (https://www.sagecity.com/gb/sage-x3-uk/f/sage-x3-uk-announcements-news-and-alerts/147993/sage-x3-latest-patches)

Information about what is fixed in which patch
Apart from checking out the information in the release notes (See article "INFO: How to find out what's new in the latest patch release in V11 and V12 - Release Notes"  ) you can also look in our "Patchfinder" utility which is also available for V12 now (Described in "INFO : Announcing the availability of Patch Finder for X3 Version 12"  )

General questions or discussions
There are other Sage City forums where you can ask general questions about Sage X3.  These forums are designed for you to converse with your peers and although Sage employees may respond, it is primarily other Sage users who are most active on these forums

"Sage X3 UK General Discussion" is the UKI specific forum (https://www.sagecity.com/gb/sage-x3-uk/f/sage-x3-uk-general-discussion)
"Sage X3 General Discussion" can also be accessed, although was originally launched by our American team (https://www.sagecity.com/support_communities/sage_erp_x3/f/sage-x3-general-discussion-forum)

If you want to do a more general search, you can use the global search at https://www.sagecity.com/ which allows you to quickly find content across all the Sage groups and products.  Of course, if you want Sage X3 specific content you can include the text "X3" in your search

I hope this article is of some help to you