How to use REST GET API Extension and save data to Bonita H2 DATABASE ?

Hi, I am a new Bonita user. I first try the REST GET API Extensions and I have some struggle that I cannot find the way to figure it out.

I have import my GET Api link, and it will output a JSON array object, Im trying to save it to Bonita DB but it doesn't work and I don't know which and how the type of variable of the outcome value I should set it to. Like I have an object Tags which have "id" and "name" in Bonita DB, I have try some way like parse to object and use COLLECT() to assign the output of the GET API to DB but it did not work at all.

Anyway, If there is anyone who have some process examples of REST API Extension or Document about how to use it in Bonita, could you share it with me? Thank you so much!!