Hi there. Welcome.
Do this:
Edit-> Species
Hit the Add Species button.
Choose a bot or two from the \robots directory of your install
Hit the Start New button.
It's a little confusing at first. Let me explain. There are two file formats for bots. One is the .txt file which contains just the DNA for a species. Think of it as a blank template - like sucking the DNA strand out of a cell and saving it. It's not the living cell, it's just the DNA - just the DNA a new bot (or 100 new bots) start from. A dbo file is a DarwinBots Organism File. It's the cell. It contains not only the (potentially mutated) DNA, but all sorts of oither stuff about a specific, running bot - an instance of a species - it's size, how much nrg it has, what color it is, it's run-time state and so on. So, you start a sim by adding the species DNA files you want then the simulator will create running bot instances starting with that DNA. When you want to save a specific running organism, you save it as a dbo.