Green Card through EB2 or EB3 is sponsored by Employer and you have to be their employee. No company will file the Green Card without being hired and placed in job and payroll running. Find a company (Direct hire or through consultancy) and talk to them before joining if they can file Green Card for you. Most of the direct hire company might not be interested to file Green Card until you work for them for at least for 6 months or so, but consultant might be once you get a job through them. That's how it works in the job market and applying for green card through EB3 (since you have bachelor degree. Unless you have 4-5 years of work experience, you can not file for EB2.)
Good Luck.