I wanted to make installing the monthly tabs as seamless as possible for you. You can download the PDF file below:
Step 1: Cut along the dotted lines and align the edge of the ruler with your planner.
Step 2: Align the tabs gently to where you want to flip to, using the ruler as a guide. Note: If you want to flip to the monthly calendars, install your tabs on the previous 'overview' page where it says 'space to plan'. Basically, install it on the page before where you want to flip to.
Step 3: Gently fold the tabs in half when you're absolutely happy with their alignment. If you were gentle enough in the beginning, you should be able to move them around a little. If you need to move them, avoid pulling them "up" off the page, and instead pull them horizontally or to the right.
Hope that helps. Happy planning!