To make a 18 volts panel, for example, you connect 36 cells in series (36 cells times 0.5 volt each = 18 volts). And 36 * 1.75 (each cell in theory averages 1.75 watt) watt = 63 watts. The amps you will be getting is 63 watts divided by 18 volts = 3.5 amps.
Most cells are 3"X6"