I found this awesome press at a thrift store! You can use heavy books too. All you need is sheets of white paper and cardboard for layering. I made the mistake of using cardboard with a ribbed texture (my dried flowers have that same texture).
Lay your specimens down on white paper and layer with white paper, then cardboard and repeat.
Sandwich as many flowers as you like! Patience is the hardest part. Let your flowers dry for 2 months.