How to go to grub menu in lenovo laptop with single boot ubuntu 18.04?

I gave my laptop to someone for installing ubuntu. Turns out he is not good at it and dont know the root password that he gave while installing ubuntu.I have seen other posts where they talk about pressing shift(and in some case esc) to go to grub menu(to go to recovery mode to solve the issue), but its not working for me.

Any help will be great as currently I have only this laptop and in urgent need for this problem to get resolved.