It depends on what tense you want it in. I lead a group is present, or you can use it for future as well as in: I will lead. If you want it to be past tense (the most common form of writing), you would say I led a group. I hope this helps :)
Lead
He led a British group.
Robert Plant.
Robert Plant was the lead singer, but Jimmy Page, their guitar player, was the producer.
The first group of Mormon Pioneers were lead to Utah by Brigham Young.
john Winthrop lead in the way 2 Massachusetts
to lead - leads - led - led
Together with President John Adams, he led the Federalists.
The past participle of "lead" is "led."
The past form of "lead" is "led." For example: "She led the team to victory."
led
Lead: Led