Hey, how do I download it?
This is a warmer, and there is nothing to download. It's just an idea for your lesson, not a worksheet.
Prepare colored letters of the alphabet on cardboard squares and put them in a bag.
Students must draw a letter from the bag, and work together to create a sentence on the board. Each student must raise his or her hand to make a contribution, but the word the student calls out must begin with the letter he or she chose. Put the expanding sentence on the board, adding words only when they the grammar is correct.