This would be one way to achieve what you have been trying for -
Job Layout -
Now, for your use case you would get the data from files - I had manipulated the data to be retrieved from tFixedFlowInput. Once you have the data retrieved you would need to perform few html formatting through tJavaFlex like below -
Once done, stored the entire content in a context variable and refer the same in your tSendMail - > "Message".
Note: there are many formatting features which could be used through HTML tags, please use them as needed as per your use case - scenario.