The only difference with a real trader is in the starting portfolio that is set in the user/profiles/profile_name/profile.json file. Each profile has its own simulated portfolio. This portfolio will be managed by OctoBot and simulated orders will be using these available cryptocurrencies as a basis. The trader simulator will use the exchanges' last trades to figure out if the current orders would have been filled or not. If they would have been filled, simulated orders get filled and the current simulated portfolio is updated accordingly.