In your practice, use the following 7 steps:
1. Play the right hand
2. Play the left hand
3. Play the pedals
4. Play both hands together
5. Play the right hand and pedals together
6. Play the left hand and pedals together
7. Play all 3 parts together
Note that the tempo for practicing should be so slow that you could literally play without mistakes in notes, rhythms and other elements of music. Aim for 3 correct repetitions in a row of each step.
Intermediate students: transpose this exercise to A major.
Advanced students: transpose this exercise to Db major.
When you are done practicing, post your time to comments.