In towny, you first join a town. You're welcome to join Opportunity if you haven't found a town already. Anyways, you use /jobs browse to find a job that suits your play style. Opportunity has a community mob grinder, so you can select the "hunter" job and make money by killing mobs there. You can then use that money to buy a plot of land that you can build a house and store items on. You can use /resource to gather materials to build with and mine for diamonds to craft tools/armor out of. It's basically survival with friends.
I apologise for a late answer to this but as a pretty much towny exclusive player I like to set myself a goal that differentiates myself from everyone else, for example have the most mcmmo, cash, largest town, best gear and best shop. the possibilities are endless and once you find a goal for you youll enjoy the server more. I set myself biggest town and for a long time I had the biggest town.
Sorry again for the late answer but I thought it could be useful.