How do I make combat boots into planters?

Here's a good tutorial on turning boots and shoes into planters: https://dengarden.com/gardening/how-to-make-boot-planters-flower-pots

The simplest way is to cut the spout end of 2 or 3 liter plastic soda bottles (so they look like vases) and insert into the boots as liners. Cut to size so they don't show. Fill with plants.

We did this with my fathers old work boots and simply put dirt in them and cut holes for the plants. There’s about 40 years ago and the boots are still good and are outside

Find a plastic container that fits inside of them, fill it with soil and plants.