I would like to press/dry some grass, leaves, and flowers.

This is usually a more long-term project. The easiest ways to dry these would be to place them between pages in a large book (like a fat old, hard-cover, dictionary). To speed up the pressing process you could put the book beneath your mattress or underneath some other heavy object.

I have about two weeks.. More if I need. Can I just stick them between pages in a book and not have them tear when I try to remove them? I was thinking about putting wax-paper around them before putting them in the book. Would that help?

Wax paper would be a good idea. Because it’s not absorbant though, it might help preserve the moistness in the specimen rather than drying it out. Maybe paper towel?

I dried and pressed stuff for years; I used a huge unabridged Webster’s Second Edition Dictionary a al Tali…but it took more than two weeks, You can also buy desiccating powder for rose buds and flowers that you want to stay three-dimensional, which doesn’t seem to be what you are asking about.

I did have a memory flash about using the microwave and found this site w. instructions:

MW drying

Why you don’t buy some already dried flowers or silk flower bits from a craft store? There are really tiny ones that will flatten nicely, and would work in the time that you have.