When you power it up with Flora's onboard switch, the matrix will display the last SMS it received. Eventually your SIM will fill up, though, as this code does not delete any messages it receives. To clean up your SMSs, load up the FONAtest code example and use the serial interface to delete them.
These pixel matrices are nice and relatively flexible, but are not designed for repeated or extreme bending. If your application puts excessive bend force on the matrix, consider adding a cardboard or other stabilizing material to reduce the amount of bend.
Unless you sewed your pouch with waterproof fabric and sealed the seams, this project is not weatherproof! If you get caught in the rain, power down your circuit and stow it inside your bag.