The object is to match the lower case letter cards to the upper case letter on the sheet.
This was perfect for my daughter since she tends to mix up a lot of the lower case letters like d, p, b, q....etc.
This is how I do the activity with her:
I put the pile of cards in front of her
"What is that?"
"Yes, that's a small 'r', where is the big 'R'?"
She does pretty well with it and enjoys it for the most part.