How can I configure the web UI on mailman3 when installed on Debian via the mailman3-full package?

I've installed GNU Mailman 3 on Debian 11 using apt install mailman3-full. I'm now trying to set up the web UI for it, as list admins will not want to use the command line to manage lists. The Mailman docs say to consult the Postorius docs. The Postorius docs seem to cover initial Postorius configuration up to creating a Django site, but give no details on how this integrates with Mailman 3 — and surely the mailman3-full package, which includes mailman3-web, should already have done this? The page at https://packages.debian.org/buster/mailman3-web implies that the web UI is visible at http://«host»/mailman3 , but it is not. It *does* say it's optional, but I can't find any information on how to configure this. lsof -nP -iTCP -sTCP:LISTEN shows ports 8001 and 8024 are listening:

python3 20949        list   23u  IPv4  97450      0t0  TCP 127.0.0.1:8024 (LISTEN)
python3 20953        list   24u  IPv4  97452      0t0  TCP 127.0.0.1:8001 (LISTEN)
python3 20963        list   24u  IPv4  97452      0t0  TCP 127.0.0.1:8001 (LISTEN)
python3 20964        list   24u  IPv4  97452      0t0  TCP 127.0.0.1:8001 (LISTEN)

but 8001 returns JSON and 8024 is Mailman's internal LMTP port. There doesn't seem to be *any* web UI exposed. I'm not a Python developer, and know little of uWSGI, which is mentioned on the page. The uWSGI documentation is massive, and doesn't really have any sections which look like they might be helpful. I can't find any instructions on how to configure the mailman3-full package so there's a working web UI — everything seems to be based around installing mailman3 from scratch, and assumes a good level of Python knowledge to boot. Please could somebody tell me how to get the web UI working? (Or, failing that, point me to a mailing list package that works similarly and isn't Mailman?)