Last time when i tried installing boot repair and fixing it, It killed my windows (windows wont load after that). So i am bit scared to use boot repair tool now.
What i currently do is when loading up i click F9 and choose the option in below image to load into zorin os. By default grub menu doesnt appear and directly boots into windows.
Please scroll way down toward the bottom until you see these two screenshots:
This is the part of the guide that you need.
In your case, check for a box to repair Windows boot - or to backup and rename Windows boot.
Ensure that "unhide the Menu" is checked and set for 10 Seconds, as well.
Continue as the guide suggests.