How does one export Minecraft "Better Together" to Remix 3D?

Recently, Remix 3D welcomed Minecraft creators to their site. The welcome blog post starts in the middle:

So, you’ve found yourself here and you’ve exported a Minecraft structure.

Wait. How do I actually export a Minecraft structure? I don't see an export option in any of the in-game menus or commands on the edition I'm using (Windows 10 edition, "Better Together" update v1.2.0).

Which versions/editions of Minecraft have added this new export capability, and how does one actually cause the export to happen from the game?

Please post a screenshot of the game's UI doing this if you can (even if it's not the same edition that I have, I'm curious to see how the game's UI works for this). Thanks!

For anyone else trying to export 3D models of their Minecraft world, this is what I know now:

• In January 2020, "Remix 3D" will be shut down, and as of now the option to upload from Minecraft to Remix 3D is gone from the game. This shutdown has not hampered the ability to export to a file locally.

• The option to export 3D models to *.glb files (glTF 2.0 format) exists in the Windows 10 edition, but does not appear available in the Java or mobile versions.

• You need to be in a "Creative" mode game with "Operator" status (the gold crown icon in the player list).

• In that game, the command is /give @s structure_block. The @s means "self" and can be substituted with any player name. The player will need a free slot in their hotbar to receive the structure block.

• Place the Structure Block into the Minecraft world, and right-click to active it. This opens a UI for choosing a nearby area to export, up to 32 x 32 x 32 in size.

• Fill out the blank name field, and adjust the size & offsets to taste, then click the Export button to produce the GLB file.

The resulting file can then be loaded or imported into most applications that load glTF, including Blender 2.80.