Can’t open GRUB in ubuntu 18.04

Its a dual boot i.e. windows 10 and ubuntu 18.04. Ubuntu is filled as preferred choice hence GRUB doesn’t come by default.
I went through many resources available and they all said press shift before the logo of ubuntu appears i.e. while the manufacturer logo is there in the screen( in my case its Lenovo ).
I have tried tapping shift continuously , long pressed shift and even kept it pressed before turning the computer ON but in none of the cases GRUB window opened. Have tried it with both left as well as right shift.I am trying to open ubuntu’s recovery mode.

Go to Source
Author: Aaryan Gupta