When you bought your bin, did it say that the metal tray is to catch the castings? If the answer is YES, you've been had. As far as I know, s o m e castings will fall onto the catch tray below but that tray is mainly to catch leachate. Please note: leachate is n o t worm tea.

To get the worm compost from bins the size like yours it's pretty much manual labour.

https://www.wormcompostinghq.com/how-to-use-worm-compost/how-to-harvest-worm-compost/

That's great information 110tis, thanks!

I may have just assumed that the metal tray was meant to catch the goodness under the wire-mesh bottoms. The methods in that link make a lot of sense. I may try the pyramid or side-to-side approach.

You're welcome HU.

When I buy pre-wash spinach I kept the plastic containers.

https://www.walmart.com/ip/Marketside-Baby-Spinach-11-oz/23848086

I use these containers when harvesting VC. instead of making pyramids on a tarp or any other flat surface. This way I can stop whenever I have to i.e. doing errands or it's getting too late in the day, without worrying that the VC will dry out too much. Also I can stack the containers and not taking up too much sq. footage of the place and have the rest of the household complain about the mess..

Have fun.

Another method to harvest in that type of bin is to place the bottom bin on top and remove the lid, place a light over top. Since worms don’t like light the will burrow down. They will move down to food and away from light. Remove the top layer and repeat. I have a similar bin (worm factory 360) and this how they recommend to harvest. Remove the lid, place under a light and come back in a hr or so (i usually could only wait 30 mins lol), harvest top layer and repeat.