Navigate to System Data > Places to create places for where the instrument is listed and traded.
Market is where the instruments are listed and the trading venue is where the instrument is traded. Some places can be both markets and trading venues like for example XSTO. Internal means that it's not a real trading place, in TRS it will get XOFF as MIC.
Once "Market" is selected, we will be able to enter it as the "Primary market" when creating an instrument.
Once "Trading Venue" is selected, we will be able to enter it as the "Trading Venue" when executing an order.