Howdy,
Inside your service panel?
It will be 4 wire connection as usual.
red + black+ and white to your neutral bar, and Green to your ground bar. Sounds funny, since your ground bar and neutral bar are connected in the service panel.
The generator neutral - ground bar is then disconnected. The generator is making use of the service panel house grounding system. That is why it is important to use 4 wires from the generator to the house. You only want 1 defined ground-neutral connection point.
example:
200 amp service panel
you will have a #6 bare copper ground wire coming from outside from your ground rod array. You will attach your generator ground right next to, or with it. You will see the neutral bar have contact with the ground bar. Other panels might have a single special screw which is installed to make the neutral-ground connection.
Always remember to use the same amperage wire all the way thru your connection.
6 AWG 4C Type W gives you a nice 87 amp limit. So a 6 AWG THHN will be wanted for its 75 amp rating. Your limiting factor will be your 50 dual pole circuit breaker here. OH, your 50 amp inlet will also be a limiter too.
Hopefully you have a service panel from one of the larger manufacturer which have a proper generator interlock available.