Pull text from imported email message

I have a table synced with my gmail account, that pulls in e-mail messaes. I want to make a button that adds a new row in an Activity table, and pull the text of the e-mail message into a field in the Activity row, but I dont find any way to get to the text so I can copy it into the new row. Any suggestions?

Dear @Tellef_Kvifte,

You can do that with a buttons as explained by @Krunal_Sheth in the below post: