New yoghurt culture arrived, now time to make some yoghurt

I ran out of my starter yoghurt culture a couple of week ago and have been struggling to find some  in the right amounts. I found a company down in Cork but the smallest delivery was working out at €130  and enough to make 2,000 litres of yoghurt.  I don't think I'm at that stage yet!So found a company in the UK that were great and it arrived 3 days after I ordered it.I made up a 1 litre starter culture using one sachet of culture. This is left for 8 hours in the incubator until it is ready, at this stage it basically is yoghurt and could be used as such...But I know that I need 15ml of it to make a litre of yoghurt and these ice cube trays are exactly 15ml each. Using a syringe I fill up the trays and freeze them to use as I need...