Service Account 101:
Go to your project in google console dashboard https://console.developers.google.com
For that in navigation menu select APIs & Services then Library.
2. Now search for Google Sheets API enable it as well.
Note: For other APIs (e.g. Calendar, Maps etc.) please enable those APIs in the Google Cloud Platform
In the navigation menu select IAM & admin and click on Service Accounts. See in image below:
On next step scroll to the bottom and click on CREATE KEY and select JSON type of key and then click CREATE, a file with key will be downloaded, it will be in format .JSON.
Open the (.json) file in any text editor and copy client_email - (e.g: firstname.lastname@example.org) without quotes.
Paste it in email settings in the Iss (account email) field in plugin settings in Bubble editor:
Note: This next step is very important so be careful!
Now copy private_key (the edited one) to plugin settings in Bubble editor:
Before that however the key should be edited first.
You will need to remove only all the "\n" and "=" characters from it and replace them with <-Enter.
This is from official google documentation (https://developers.google.com/shopping-content/v2/orders-best-practices) :
After you did that, paste this key in plugin settings, it should look like this:
You're all set to work with a Service Account.