Oh sorry I'm being obtuse. The section that looks like the foot should be separate from the upper shin section. Might be easier to explain with the following pics of Alia's boots; together
. White blob is the foot section, burgandy/pink is the shin section.
I will caution using papermache. It does work but it will pinch the back of your legs and breaks easily. But it is cheap and fairly easy to start once one remembers to seal (aka cover in tape) any cardboard you use as a base. It's been a while since I used papermache but I remember the epic fail that was my staff made out of papermache over plain cardboard. It warped really badly. >.<