The signal generator has a 50 Ohm output with BNC connector. Ideally, you connect this with a BNC-to-BNC cable to another piece of equipment that has a 50 ohm terminated input. Proper cabling and termination are only actually important for higher frequency (>MHz for sine waves, or any square wave or pulse output). As mentioned by others, if you just need to inject a signal into something, use a BNC-to-whatever cable (BNC-to-croc clips is handy), but know that this works well only at sub-MHz frequencies. Keep in mind that if not terminated into 50 ohms, the output voltage may be 2x as high as expected. This is because the 50 ohm input impedance effectively forms a voltage divider with the 50 ohm output impedance of the signal generator. If the impedance is higher, like the 10 to 100 kohm input impedance of an audio amplifier, then the voltage will be higher. Many signal generators have an output impedance switch to select 50 ohm or high-Z - this doesn't change the output impedance of the signal generator (it's always 50 ohms) but adjusts the output voltage to compensate for the expected loading so that you get the waveform amplitude that you have selected.