One you have an account, you can access the career site to update your information, see your activities, search for jobs, and apply.
Though each career site may be slightly different, all have a similar approach to what we describe here.
Log in to the career site with your username/email and password
This will take you to your account. Here you can see recent activities, update your profile, and see the status of job applications. You can also choose a file to attach your resume and reset your password.
From the main pages, you can find links to search for job opportunities
The job search is based on various criteria to help you narrow down your results.
When you find the job you want, select apply and the information in your profile will be attached to your application.
Recruiters will see your application and hopefully contact you.