A profile holds all your OBS settings, it does not include scenes or sources. But it allows you to have a profile for each Channel you are streaming to or for different recording or streaming settings.
As soon as you change a setting in OBS it is saved to the current active Profile. So before you change your settings, create a New Profile using the Menu. Then you can edit your bitrate, resolution, streamkey, or whatever you want and it is saved to the new Profile. Afterwards you can switch back to your old settings by selecting the old Profile.
You can also duplicate your current Profile into a new one, if you only want to tweak or change a few settings but keep the rest. And you can import or export your profile to exchange it with friends. Be aware though some settings might not work perfectly as intended on a different computer system.