You can customise your keyboard shortcuts by doing the following:
Step 1: Right-click on the ribbon to open a context menu and select “Customize Quick Access Toolbar”
Step 2: This will open a new dialogue box. At the bottom of this dialogue box there is an option “Keyboard Shortcuts” with a button that says “Customize” select this button
Step 3: This will give you the “Customize keyboard” options. From here you can select an option and add the keyboard shortcut that you wish to use.