Click the Open/Opening Shift button; when the confirmation dialog appears ("You are about to open a cashier shift..."), click Yes.

The Cash Breakdown - Opening window opens. Enter counts for each denomination (1000s, 500s, 200s, 100s, 50s, 20s, 10s, 5s, 1s, coins) in the boxes.

Verify the calculated Total Amount, then click Save to record the opening cash and start your shift.