Connecting to a PL/SQL Database throught external task

Hi at all! I am new to Camunda and just started to learn it. I have a simple process(attached below) for transferring and save data from input forms to a database. I’d like to use an external task for service task. Programming language for external task is node.js. Service task should collect data from input form transfer and save it to PL/SQL database. Therefore, I have two questions:
1)How can I collect data from inputs to a service task? As I know I can do it with Java classes and I have no idea how can I do it within an external task.
2) How can I establish interaction between Camunda, Service task and database? Should
I connect to a database for transferring data within Camunda or within service task or both?
Best regards,
Max