Anonymous, only level 1 of harvesting is available on the trial version, and researching and buying this will help to save your villagers from starvation.

Future levels can require a bit of planning to get to, but there are plenty of tips available on the forums to help with any problems that you have

I have heard of other players who have been able to drag the trial version out for quite a while, so if you need any other pointers, you know where to ask