Advice on the type of JOIN I should use in this scenario using MySQL Database

I have 3 sections as follows;

  1. TIER I
  2. TIER II
  3. TIER III

Each having tables as below

  1. Objectives
  2. Performance Measures which references Objectives
  3. Performance Actual which references Performance Measure

The Objectives of Tier II references those of Tier I & those of Tier III references those of Tier II.

My requirement I want to get Tier II Performance from Tier III performance, and also get Tier I performance as from Tier II performance.

What I have Tried

SELECT   d_o.ObjectiveName,   ia.Q1 AS 'Q1Actual',   ia.Q2 AS 'Q2Actual',   ia.Q3 AS 'Q3Actual',   ia.Q4 AS 'Q4Actual',   i_o.ObjectiveName AS 'Individual Objective',   fy.FY AS 'FY',   AVG(ia.Q1),   dpm.DeptMeasureId,   dpm.Q1,   ia.* FROM   individual_appraisal ia   LEFT JOIN individual_pm ipm on ia.MeasureId = ipm.MeasureId   LEFT JOIN individual_objectives i_o ON ipm.IndObjectiveId = i_o.IndObjectiveId   LEFT JOIN department_objectives d_o ON i_o.DeptObjectiveId = d_o.DeptObjectiveId   LEFT JOIN department_pm dpm ON dpm.DeptObjectiveId = d_o.DeptObjectiveId   LEFT JOIN tier_one_objectives t1_o ON d_o.TierOneObjectiveId = t1_o.TierOneObjectiveId   LEFT JOIN financial_years fy ON t1_o.FYID = fy.FYID WHERE   i_o.StaffUser = 'staffuserName...' GROUP BY   dpm.DeptMeasureId 

Note I have attached a database diagram for the same to better understand the question. Database Diagram for the above Illustration.

Your kind help is highly appreciated.