The most drastic change in maintaining the website is the move away from a set of html files in a version control repository to a content management system (CMS).
This brings some changes that take some time to get used to. This introduction should give a small overview on how to use silverstripe (that's the name of the CMS currently in use on libreoffice.org)
Slow my friend :-) - you first need to create a login - to do so visit the registration page at https://www.libreoffice.org/ForumMemberProfile/register and request edit and publish permissions on the firstname.lastname@example.org mailinglist
Once you created the login and got edit permissions granted, you can login to the CMS by appending "/admin" to the URL of the site - e.g. by visiting https://<project>.libreoffice.org/admin - replace <project> with the name of the project you want to edit. In case you got permissions to edit multiple projects, you can choose either one and afterwards switch sites within the CMS.
This is what you get when you login (labels differ of course depending on what CMS locale you did choose when you did register). The CMS has a category selection at the top: Pagetree, Files & Images,.. (depending on your privileges, you might see more items) and also the subsite selection mentioned earlier (in this case read only, as the user only has access to the German NL-project)
The page tree and the content area are the most important parts, thus they deserve an extra heading, so move on to the footer - that features links to the published (as seen by a regular user visiting the page) and to the draft site (the site has been modified and saved, but not yet published), and of course also features the logout link at the lower right.
Giving you checked the 'Help' tab and created your first pages according to the brief manual there you might want to have the homepage, your landing page defined.
Go to the 'Metadata' tab of the page and rename the pagelink to 'home'. Insert metadata instead to attract crawlers.
In case you like the link and want to keep it, go to tab 'Behaviour' and define the homepage by inserting <$subdomain>.libreoffice.org without http at the bottom of this page. Certainly you will replace <$subdomain> with yours.