What was the main reason the Separatists (Pilgrims) left Holland?

They feared losing their national and communal identity.

What challenges did the Pilgrims face when they first arrived in America?

The Pilgrims didn't know how to fish, food was running out, and they resorted to stealing from graves and homes.

Squanto was a Native American who spoke English and taught the Pilgrims how to grow crops and acted as an interpreter.

I can describe the events that led to the first Thanksgiving.

1
At the start of the 17th century, southern New England was home to a variety of busy communities within several confederations known as the People of the First Light, who called their home the Dawn Land.
2
The Separatists, later known as Pilgrims, sought a patent from King James to build a colony in America, planning to profit from catching fish to repay their investors.
3
During New Plymouth's first year, Squanto plotted to overthrow Massasoit, but his plan was discovered, leading to further tensions between the settlers and the Wampanoag.