Get string from dynamic content

[mab17]

I have created a sequential approval flow for a process in our company where a team of employees each have a step required to approve before the next employee completes their task in the flow.

Here's the beginning of my flow:

1) When and Item is created

2) Start an Approval #1

3) Condition (Approved or Rejected)

4) Email employee

5) Update item

6) Start approval #2

etc.

As I use the Dynamic Content to populate some of the fields in these steps (Approval, Email, Update item), Microsoft Flow shows multiple options for "ID" for When Item was created, or "Update Item".  As I get further in the flow build, with multiple approvals and multiple update items, the list grows.  As I'm still fairly new to Flow, How do I best select the correct dynamic content?  I am getting some failures to my flow and see from the Error's that some of the dynamic content is not being accepted.  I'd like to best understand the process here to avoid future Flow Fails.

Thanks.Here's an example of the dynamic content options I can use. how do i know which ID to select?Here's the beginning of my sequential approval flow