Printing content from picturebox c # to thermal printer (zebra) by serial connection

I received a job order to print bar codes on the printer you have here ( Zebra QL320 plus 1 ). The first step is done, I was able to adapt a code to generate the bar code; it is inserted in a pictureBox . My great doubt and obstacle is how will I send this image via serial port to be printed? And how do I adjust the print layout to print two copies of the bar code next to each other and a third copy right after the size of the label. I found this question here from the site but is being used a string , that is, text will be printed and in my case it is a bitmap image. Is it possible to do that? I also saw about the layout that he used ZebraDesigner2 to adjust, I just downloaded and I'm going to test. I'm a beginner in the area and it's my first job so it's very difficult in this part, I never programmed something that has a connection with anything, be it serial, bluetooh, usb, etc and I did very little with C #. Thank you in advance!