First off, here's the data sheet. You'll have to send it a clock signal from one pin of your MCU. Then just before you send it the data on a second pin, you'll have to set a thrid pin of the MCU to high to set the enable bit. Each bit of the data signal corresponds to one of the segments in each of the 4 digits. The details are in the data sheet. MikroE has a pretty good forum. Have you asked around there? Someone might have already created a library for this.