Symmetrical modeling help

I just got Blender today, watched a few tutorials, and I have started trying to model some. What would really help with the modeling is if I knew how to set it to symmetrical modeling, like I saw the guy doing in one of the tutorial videos. If anyone knows how to do that or a video that shows me how to do that really easily, that would be great!
thank you!

Hi what you need is the mirror modifier. Here a video at youtube
I haven’t watch this one but it should be ok as I’ve seen their other videos.
Or just google 3d blender mirror modifier.
Good luck and welcome to the boards.