Click on the tag icon then scroll down the variables. It should be able to show the variables of the GSheet.
This way, you can use the variable to send follow up, confirmation message and others.
You can continue setting up the flow as needed and then save it in Flowbuilder. While configuring the flow, you can keep the toggle at the top right set to **Draft** to prevent contacts from triggering it accidentally. Once everything is ready, switch the toggle to **Publish**.