By looking at your flow snapshot it seems like you are not setting up the excel card correctly.
Where is your excel file? On dropbox, ondrive google drive etc? File name also seems wrong since you are appending tweet text to the file name.
The right set of steps to use this template would be-
1. Create a table in an excel file and add the excel file to one of the file providers like Dropbox, Onedrive, Google Drive etc (For this scenario you can create a table with columns like Tweet id, Tweet Text, Tweet By, Tweet Time etc).
2. Create an excel connection (You need to specify the file provider and enter the credential of your file provider account like google drive email id and password)
3. Use the file browser to select your excel file (Click on ... besides File name field)
4. Click on table name dropdown and select your table.
5. Once you select the table, The table column fields will start apearing on the card. Now you can populate those column fields with the tweet output fields like "Tweet Text", "Tweet By" etc.