Importing Event Participants with Contribution/ Payment
The way to do this is to import the Contributions and Participant records separately via the CiviCRM import tools. You may need to also import any new contacts you have first. Using the import tools takes care of all the extra complicated tables.

Then to connect the Contributions to the Participants: 
You will need to export a csv of all the imported Contributions and a csv of all the imported Participant records. Match up those two lists based on the Contact ID. Then you will manipulate that data to be importable into the civicrm_participant_payment table. Which is just Participant id and Contribution id. 

Then you will have all data where it needs to be and properly connected