Once you have all the necessary information, you and your employer complete the ETC certificate of engagement form (put your passport number in the Identity Card Number box if you don’t yet have a residence card) and submit it to the ETC office.
Take the form, along with your passport, social security letter and work contract to the office on St Zachary Street in Valletta – opposite Next and one to the left, it’s a very inauspicious-looking place. If you’ve got everything else ready and you are early enough, you can go to Apply for your Maltese Residence Card on the same day
Attaching the form to an email along with your passport, social security and work contract and sending to firstname.lastname@example.org (that email address is not so reliable. I never heard back so just took my documents in and was given the certificate within half an hour by the helpful staff). On the other hand, if your workplace has a competent HR person to send the forms for you, you won’t need to worry about this.