This quick step-by-step tutorial will guide you in your first steps.
Let's take a look at some sample data. Keep in mind that the email addresses and card IDs are generated, so your data in those two columns will be different from the picture below.
The email column contains recipients. Then there are three empty columns which will be populated by the add-on. Data from the last three columns will be merged into Gmail messages.
The add-on created a sample draft named Membership Cards. When you go to Gmail Drafts you can open it and see what is inside. You will notice a couple of merge fields there. Merge fields will be replaced with values from columns based on the mapping configured in the mapping editor.
Select Process all Rows and hit the GENERATE button.
Once the merge job is completed, the Draft Created column contains timestamps and the Draft ID column contains IDs.
Go to your Gmail Drafts folder and you will see eight new drafts there named Membership Card. Take a look.
Switch to Draft to Send mode. In this mode, the add-on takes IDs from the Draft ID column and sends the corresponding drafts. Once a draft is sent, the add-on removes its draft ID from the sheet. Start the merge job and click the SEND button.
The add-on will send emails to Mail Drop service. Once the job is done, check your Gmail Drafts folder. Only the template draft is left there. All other drafts were sent, and now you can find the messages in your Gmail Sent folder. The data in the sheet should now look like this, with Email Sent timestamps set and Draft IDs removed.
Now you can check the messages in the Mail Drop service. Just keep in mind that it might take few moments before a message appears there. Take the first part of the email address, before @, enter it the input box in the top right corner, and click View inbox.
The first email address starts with 6nsm (these addresses are generated so you will have different email addresses in your sheet). Paste that there. You can also use the Mail Drop service to test your emails in your future merge jobs.
And that's it. You just ran your first merge job. You can edit the Membership Card template, so try to add new merge fields and map them in the mapping editor. All of that should be self-explanatory. If not, and you are stuck and need help, you can always ask a question in our Google Group.