You can pay a few hundred dollars to a cram exam company. And get your license. Or you can study on your own and take the tests.
Here is the FCC web page for the requirements.
FCC: Wireless Telecommunications Bureau: Types of Licenses: General Radiotelephone
You need Elements 1 and 3 for the GROL. If you want the Radar endorsement also. That's number 8.
Here is the FCC web page for the questions.
Commercial Radio Operator License Program: Who Needs a License: Exam Question Pools
Once you study. You need to find a computer testing place to take the exams. I did mine at a Sylvan testing center. But that was a long time a go. Not sure who does them know.
Take the tests. Fill out the FCC 159 and 605 forms. And it takes a couple of weeks to get your paper license.