Let the ice cream soften a little bit, then stir it together with the root beer in a bowl using a wooden spoon until smooth and creamy. The mixture will be frothy and that is just fine.
Place the popsicle sticks into your popsicle molds, we prefer the silicone molds linked below when making popsicles
Pour the root beer mixture into your popsicle molds
Freeze for at least 2-3 hours (I like to check after 2 hours and see if they've firmed up, especially if little hands are waiting :) )
Remove from molds and enjoy!
Notes
If your popsicles stick to your popsicle mold try dipping the bottom of the mold (not directly touching the popsicles) in hot water and they should slide right out.
If you want a creamier popsicle add more ice cream to your mixture.