How to install lower control arm on ford taurus,what do I remove first.

This link will help "big time." The trick is to lower the sub-frame, in order to free the lower control arm from the ball joint:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-9.html#post1691894

While you have the steering knuckle off, consider replacing the wheel bearing and lower ball joint.