Same as anyone you apply for jobs that are advertised , you contact any employment agents , you send out your resume to companies and even cold call companies.
Nobody is going to just give you a job when you get off the plane and it may take months to find a job. You may even find that you never find a similar job to the one you are doing in your home country .
Immigration is not an easy choice to make and people have to put in a lot of effort to succeed, years maybe.