Step 1: Cut your snowflakes
Note that the left and right of the unfolded flake are slightly different from the top and bottom. You can put that cut in after unfolding once.
Step 2: Glue the flakes together
Step 3: Unfold into a tree shape
Unfold the bottom of each flake to make a stand of sorts, which you should glue to a baseboard (with a nice little note written on it, if you'd like).
You can also bend out the bits of each flake that you haven't glued together to increase the 3D effect.
Step 4: Invent an ambigram
That's ok. They're not so hard. Be sure to pick phrases of comparable length and... get creative! This ambigram generator only makes 'rotational' ambigrams, but it's a good place to start.