Snom 300

Transfer a call...

Press the unused line key, dial the extension required, then the tick
When answered introduce the call then press the transfer key
Replace the handset
Job done

Listen to Voicemail for the handset you are at

Press the message button (envelope)

Listen to your own voicemail

Dial *98, then you will be asked for your mailbox, and then your password

Record your voicemail message

Having reached the voicemail in question, press 0 (zero) and follow the instructions which are as follows: -

Press 1 to record your unavailable message. This plays if you do not answer
Press 2 to record your busy message, this plays if you are on the phone
Press 3 to record yoru name, this can be used by a default message, not much use really
Press 4 to record a temporary message such as "I am in meetings for the next two days, please call my colleague"
Press 5 to change the password of your mailbox