You look for projects that fit your skills and then you send an application. In your application, you will answer questions that the employer has chosen and will send your resume. You also submit a bid on how much you want to be paid per hour or how much the project will cost overall depending on...
Once you have been accepted for a project, you complete it to the specifications given to you. Every job is different. Sometimes the employer expects a lot of communication, sometimes they do not want much, they just want a finished project by the deadline.
