Start by painting the paper mache boxes in the color of your choice. You will need to paint both the top as well as the bottom. With paper mache, always do light coats of paint. Then allow to dry and add another coat. These boxes took me approximately three coats for full coverage.
While your paint is drying, you can download the conversation heart cut file above. Then upload that cut file to your Cricut. Cut the designs from vinyl. Then weed away all of the excess vinyl around the outside as well as the centers of letters.
You will then need to use transfer tape to move the design from the backing paper to the paper mache boxes. Paper mache can be delicate so I recommend cutting a piece of transfer tape to the size of your design then sticking it to your shirt a few times. This will make it less sticky and therefore less likely to damage your paper mache. Then use the transfer tape on the top of your design and burnish well.
You can then remove the backing paper from your design and get it ready to add to your box lid.
Carefully place your design on the box lid. Make sure it is in the correct location as you will not be able to reposition it.
Burnish it well then peel back the transfer tape. Be careful when pulling back to ensure that the paper mache is not damaged.
Then just repeat this same procedure for as many Valentine heart boxes as you want to make.