To send a message to the Vice or to all Club members, simply click on the club button (indicated by the red arrow in the following image). 

then press on the envelope at the top left under the Club logo (indicated by the red arrow in the following image)

at this point you can write the message and click on:

a) Only Send to te Vice if you want to send it only to the Vice

b) Send it to all if you want to send it to all members of your Club