This page of the guide to Dragon Ball Z: Kakarot has a walkthrough for the following missions: A Glimmer of Hope, Enter Super Vegeta.
DBZ Kakarot - A Glimmer of Hope
Time for Goku and Gohan to enter the Hyperbolic Time Chamber. As Gohan, you have to fight Goku (level 41). Your opponent won't fight seriously. Avoid Goku's Kamehameha and counter with your powerful Ki attacks. Dodge a lot to defeat Goku fast.
Kakarot DBZ - Enter Super Vegeta
It is time to see the results of Vegeta's training. Fly to Cell (level 37), and you will start the fight. The fight will be very simple - you have a much higher level and strengthen attacks. Cell's second form is nothing for Super Vegeta.