Linking events participants and contributions
you have a create participant record in civicrm_participant table which will have the Event Id in the table, participant and contribution should be linked using civicrm_participant_payment which will have contribution_id and participant_id. This is how you have to do 

One more suggestion: before doing anything data import install a fresh copy of civicrm and delete all the relevant table records and make a test process by creating Event and registering the event for an member and look which are the tables been affect and please update the values based on the test