I'll make it simple and I'll edit it sometimes!

Step 1):Go to https://obsproject.com/download and downland the programm OBS(Open Broadcaster Software).
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First of all,you need to set the broadcast settings!
Check the below photo!
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At 'Ecording' you need to check your upload speed first at speedtest.net and then you can go at https://obsproject.com/estimator and fill the boxes,based on your choices.I have the below settings,but you don't have to set the same.
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Step 5):About the audio,if you want to set ON your microphone choose your microphone device and set it.The same goes for the sound.Choose the device you want to use at OBS.For example,if you got 2 devices for sound,1 headsets,and 1speakers,you can set audio from the headset,and WHATEVER you hear from the headset,it's on the stream.
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I will keep editing it,everyday.Comment below if that helped you,if you got any questions.