Manually Downloading Tor Browser
The Computer Security Education page contains a chapter recommending to learn the basics about torproject.org's Tor Browser before starting with Whonix.
For example, in past before the introduction of Tor Browser's Internal Updater, the recommended way by The Tor Project (TPO) to update Tor Browser was to rename your old folder (for example /home/user/tor-browser_en-US to something else) (or delete it) and to extract the newly downloaded version. You won't know about such glitches, if you don't know the basics, namely how to use Tor Browser on the host.
General questions like how verification of Tor Browser works, what that's good for etc. are off topic here, since we have to unfortunately regard this as basic knowledge. Whonix is not a standalone package in that sense and just has a small team while torproject.org has a much wider community and dedicated support staff. Again, you need to imagine you know nothing about Whonix and need to learn basics about Tor Browser in the first place.
If you are experiencing an issue with Tor Browser in Whonix (for example, some page does not load), please check first if you experience the same issue with Tor Browser on your host. If that is the case, Whonix is not responsible for this error. If you care to see the bug fixed, you are advised to search torproject.org's bug tracker and to open a bug upstream if no one else reported the issue yet. When upstream (TPO) fixes the issue, the issue will most likely also get fixed in Whonix.
Sometimes Whonix's Tor Browser Downloader breaks, because torproject.org changes the way Tor Browser can be downloaded/verified. Since Whonix's Tor Browser Downloader is maintained by the Whonix team, The Tor Project is not responsible for it and it and therefore should be discussed in Whonix's User Help Forum or Whonix's Bug Tracker.
At time of writing, there were never any errors in Tor Browser (such as when a page doesn't load) caused by Whonix.
Manually Downloading Tor Browser
If Tor Browser is not installed, then it can be downloaded by using Firefox-ESR, a web browser that is already installed by default in Whonix-Workstation.  Use it to download Tor Browser only.
|Qubes users note:|
AppVMs: The following instructions are supposed to be run within Whonix-Workstation AppVMs (commonly called anon-whonix).TemplateVM: For Qubes-Whonix whonix-ws TempalteVM, you should know that upgrades of Tor Browser in the TemplateVM are only inherited from newly created AppVMs. Additionally, rather than storing Tor Browser in /home/user/.tb you would have to use /var/cache/tb-binary/.tb. For background information why that is, see Tor Browser, Qubes specific.
|Note on platform support:|
1. Navigate to http://rqef5a5mebgq46y5.onion and download the Tor Browser for Linux. Store it in /home/user/.tb.
2. Read https://www.torproject.org/docs/verifying-signatures.html.en and learn how to perform GPG verification.
3. Navigate to https://www.torproject.org/docs/signing-keys.html.en to download the relevant GPG signing keys.
4. Verify the Tor Browser download.
5. Navigate to /home/user/.tb with the file manger. Dolphin example:
Show Hidden Files
6. If the old version of Tor Browser is still open, close it.
7. Rename the old /home/user/.tb/tor-browser to something else.
8. Extract the Tor Browser.
Right click on the downloaded archive ->
extract archive here
9. The process is complete.
10. To start it, navigate to the /home/user/.tb/tor-browser folder and double click start-tor-browser. 
|It should be clarified that this will not result in a Tor over Tor scenario when using Tor Browser. Whonix has a mechanism to disable Tor stacking.|
https | (forcing) onion
This is a wiki. Want to improve this page? Help is welcome and volunteer contributions are happily considered! See Conditions for Contributions to Whonix, then Edit! IP addresses are scrubbed, but editing over Tor is recommended. Edits are held for moderation.Whonix is a licensee of the Open Invention Network. Unless otherwise noted, the content of this page is copyrighted and licensed under the same Libre Software license as Whonix itself. (Why?)
- If necessary, Firefox-ESR can be manually installed via a terminal:
sudo apt-get install firefox-esr
- Qubes-Whonix is 64-bit by default. The 32-bit version should also work, but is not worth bothering with.
- Until Whonix 14, the default download version of Whonix is 32-bit. Therefore, 64-bit software won't run unless Whonix is built from source code.
Or type in a terminal.