Tabletop Simulator Export
One of the really neat things about Dextrous, is we have the fastest Tabletop Simulator export in the business.
While you can always export pngs and upload the TTS the traditional way, we have a much faster custom pipeline which most designers use which involves us:
Hosting spritesheets on our server
Creating json files that you can drop into games easily (along with different export types like cards, tiles, tokens, custom objects, etc.)
Export to Tabletop Simulator in 4 Steps
You can export deck/s to TTS using these steps:
Export to TTS from Dextrous
Download the TTS json file
Put the exported json file in the TTS Saved Objects folder.On Mac, you'll find it at Library/Tabletop Simulator/Saves/Saved Objects. If you can't see the Tabletop Simulator folder in your Library folder, press Command+Shift+Period (.) to reveal hidden folders in your Library. Thanks uncle Mac! 
On Windows, this is at Documents/My Games/Tabletop Simulator/Saves/Saved Objects:
On Windows, this is at Documents/My Games/Tabletop Simulator/Saves/Saved Objects:
Finally, import the json object into your TTS game by clicking Objects > Saved Objects and selecting your file:
Pro tip: Bookmark the Saved Objects folder (add to favourites or your taskbar/dock etc.) so you can stop scrabbling round like a n00b every time you export!
Tabletop Simulator Export Video Tutorial
Watch this tutorial for a quick run down on how to export your Dextrous components to Tabletop Simulator.
Updating a TTS saved game in-place:
Once you've imported Dex json files, save your TTS game.
In Dextrous, make any changes you need, then export to TTS again. This time you don't need to download the resulting json file (the component sprite block will be updated if you've made any changes).
In TTS, quit to main menu, then load your saved game. It should now have your updates!
Please note if you've changed the order or number of cards in your component you will need to reupload the TTS json (updating in-place like this won't work).
Note: if you're making a TTS mod specifically, you'll need to get players to turn off mod caching (Menu > Configuration > Mod caching) to get your updated changes. Sometimes we've found restarting TTS is also necessary.
Objects and Tokens and Cards (oh my!) 
You can set your component to export to TTS as a custom object, a token, or a card.
Select the type in the component settings menu, under Tabletop Simulator settings:
Objects
Custom objects are generated based on the clioppath shape of the base zone (card_background) in your component's layout. Click the base zone and select a clippath shape (). To remove a clippath, click the X button in the top left corner:
Tip: you can also make your own clippath shape in the editor below, and save it!
If you don't have a clippath applied but have selected 'object' as the TTS component type, Dex will give the component a basic square shape.
Legacy note: It used to be that if there was a clippath shape on the base zone (card_background) of a component's layout, Dex would automatically assume you wanted a custom object (we called these 'tokens'). It works the same way now except that you have to explicitly select 'custom' as the TTS component type - otherwise card is the default TTS component type.
Tokens
Tokens are a new export type. Tokens are generated by TTS on the fly (TTS cuts out transparent bits of the layout). Tokens great for polyomino games or if you want different shaped tokens within the one component.
In the example below, you can see 3 different cards in a single component. The colored squares are zones which are positioned on a transparent base zone (card_background) in the layout. When these are exported to TTS, TTS will 'cut out' the shape and ignore the transparent backgrounds creating legit polyomino tokens!
Cards
This is the default setting for exporting to TTS. Your component will come into TTS as a deck of cards which can be shuffled and combined as a normal deck of cards.
Using TTS custom data
In this tutorial, you'll learn how to use TTS custom data (such as snap points) in Dextrous, but you could also use this same technique to grab any kind of data out of a TTS object (like scripting for example).
This is a fairly advanced technique, but hopefully it opens up some deeper options for game designers out there.