I made a video tutorial Build a Web of Things project using the WoT:API module. This video contains the entire process from enabling the module to lighting the LED. The main demonstration content is as follows:

I created a route /things/{thing_id}/actions to execute the action that the user requested through the POST. Interface description: Actions resource. 

To enable the user to add a Thing Action to a Thing, I create a custom Thing action field to associate the user-created Thing Action with a Thing.

The user needs to create a custom Thing Action and then choose which Thing Action to add when creating a Thing.

I don't think actions should be predefined. This is the description of the Action object.

2.11 Action object
An action object describes a function which can be carried out on a device.

Answer the previous question mentioned in the blog post.

How does type restrict the type of field that stores the property value?

Since the JSON:API code base is very large, after copying the jsonapi module into the wotapi code base, I deleted a lot of things, such as the Query folder, but it was not enough. Cutting out the code base makes it easier for me to move forward.

As I mentioned in another blog, I can edit the value of Thing property when creating the Thing entity by Inline Entity Form (IEF).  After adding an Entity Reference type of field, commonly used WIDGET is Autocomplete/Autocomplete (tags style) instead of IEF. In the case of points, IEF is used by default after adding a field of entity reference type where the target type is points.

In the past few weeks, I have been thinking: why does the Property object in Thing resource not contain the value of the Thing property? It's clear that ‘type’ refers to the type of value the property stores, and the property itself is an Object containing fields such as title, description, and so on. 

Property object:

Last week, I try to show mentor the demo of property. So, I add a new field to the thing bundle. When the mentor saw that there was no Thing property to add a new field, he asked me: why is there no Thing property? I said Property is in Other of Reference category. But he said it should be shown on the outside, and I insisted there was no difference. Finally, of course, I need to research how to make the Property display on the Other... of Reference.  Because he thinks Property in Other... is hard to understand and also Thing property is easier to understand than Property.

I made a mistake last week. Thanks so much for the mentor pointing out my mistake. I filled in the wrong data in the screenshot of the blog for testing. The mentor found the problem after reading, and we spent a long time discussing related content. I placed the field that should be defined on the property entity incorrectly on the property bundle.