I tried to put a short help for probably the most frequent posts/questions soon to expect.
(Sorry for cross-posting, I first put to the old and cluttered General Magisk thread but this is now better place)
Please carefully read Magisk Changelog and OP posts in this thread
Study the Magisk documentation from the official Magisk Github page - particularly about installing Magisk (if not familiar with patching the image in Magisk app and flashing the patched img from Fastboot- different from the old school about flashing Magisk zip through TWRP)
a) No more MagiskHide. New technology instead (for more or less the same - to help hiding root): Zygisk+DenyList
b) No more built in SafetyNet checker. Install from PlayStore e g: YASNAC to check your SN
c) Modules window does no more connect to the old Modules repository.
You must download module zip files manually and "Install from local storage".
Or search for and install Fox Magisk Module Manager (Fox Mmm) app - it will connect to the new, alternative repository and the old 'official' repo, allowing you to install from both
0) If upgrading Magisk and if you previously did "Hide Magisk app/Mngr" from Magisk app/mngr - always "Restore Magisk app/Mngr" before upgrading Magisk
1) Make sure that both Magisk app and Magisk are installed and updated to the new version v24 version. Inspect version numbers on the main Magisk window/page
2) Make sure to uninstall all Riru modules (Riru is not compatible with Zygisk that comes with Magisk v24)
3) Settings, Enable Zygisk and reboot.
Then check on the main window does it show Zygisk Yes
4) Settings, enable Enforce DenyList.
Configure DenyList, enable filters to Show OS and System apps.
Find Google Play Services and check-in only the two processes ending with gms and gms.unstable.
You will have to check in all your banking apps and so as you used with MagiskHide.
Always reboot upon reconfiguring DenyList
5) If SafetyNet does not pass, install USNF 2.2.1 and test again.
Always reboot upon installing a module, also if/when you enable Systemless Hosts
Note: Once you install/enable USNF 2.2.1, it will remove Google Play Services from your DenyList - but don't worry, USNF takes care of GMS
6) If you are on non-certified custom ROM and you still don't pass SN - then you will need Magisk Hide Props Config module - check for and consult the MHCP thread
If you want to hide Zygisk, then instal Shamiko module - and you must disable Enforce DenyList (although DenyList must stay configured).
But Shamiko is really not essential (might help for some banking apps but it's irrelevant for SafetyNet)
Banking apps - out of scope for this post (also, this thread is about the Magisk v24 itself, not abkut the particular banking apps)
Go to Magisk Github documentation, read Wiki, there is a section with tips you should try first
If putting your banking app to DenyList (now, instead of the old Magisk Hide) and hiding Magisk app does not help, and the other tips from Wiki do not help (like renaming TWRP folder and so), search in this thread how to use Hide My Applist (Zygisk-LSPosed module)
Every time you apply another tip to your troublesome banking app - go to Settings, Apps, and delete Cache and Data for that banking app before you try to open it again (some apps will cache that they previously found the phone was rooted)
Even with HMA, there are certain banking apps that cannot be tricked (on some phones like Xiami, etc)
Momo - absolutely not essential for your life
When you pass SN, Momo might still detect that your Bootloader is unlocked - you cannot hide it from Momo on e.g. Xiaomi phones
Generally, treat Momo as 'banking' apps (add to DenyList and reboot)
Momo does not look for apps (Magisk app, LSPosed mngr, LSPosed modules), hence for Momo you don't need to bother with HMA
Basic tips for Momo: Remove/rename TWRP folder, disable USB Debugging - for the rest, search for Momo posts in this thread - but still, there will be findings you could not hide from Momo (not encrypted Data, custom ROM, etc)
PS: Magisk Alpha v24.1 (vvb2060 and her team) has departed their way (different package name, revival of MagiskHide?), hence this post is now (mainly) for the official TJW Magisk Stable and Canary v24
(Some parts do apply also to Alpha but use Alpha on your own risk and ask the other Alpha users about the Alpha status and practices)
Last but not the list - there night be specifics for certain phones (like flashing with Odin for Samsung, end so on)
This post is generic, for your specific practices read/search through this thread and also on your phone/model subforuns on XDA