I understand the desire to control the display of topics, but this works against the principles of the design of the platform as a community tool- it is meant to be the result of actions that take place by your community.
In using Discourse now twice to run an online conference, I have to keep reminding myself and colleagues that it’s not as controlled as a web site. I have found it best to loosen as much as possible the idea of “controlling” the display beyond making categories.
So in our conference category, I have several sub categories to organize individual sessions by modality (keynotes, posters, live webinars) - here is our recent conference, where the blue boxes are conference information subcategories and red boxes are session subcategories
but have to remind people that it’s not the viable way to browse for sessions
For pur events, this organizing of topics to make more browseable friendly is in creating a seperate post/Published Page (see below) as a schedule, or an ordered list of the topics in a meaningful way. For our conference, I built a series of topics in a schedule subcategory (where replies and topic creation are closed), where each day has its own topic and links to the others within.
The “solution” is maybe to as suggested, use a pinned topic, but rather than trying to pin all the ones you want to order, that you pin a post like “New Users Start Here” or “Getting Started Guide”, and within that, create in the post a welcome message and the topics linked in the order you want to proceed. That way you just have one pinned thing. At the end of each one, you can even add a link, button to take them to the next or previous.
To make it cleaner, you can also use the option under primary topic (three dot menu, then wrench, then select Page Publishing from the menu)-
this converts the topic as a stand alone page (like the difference between WordPress posts and Pages?) that does not include the topic interface. This exists at a more or less fixed address you can share as a link for new users.
I use this on our space to provide a getting started guide https://connect.oeglobal.org/pub/connect-guide