Create the appropriate DNA sequence, insert in a selectable plasmid with a good promoter (plenty are available on the market) transform an innocent E. coli, select and feed and you have plenty of your new protein.
This is a rather rough sketch to answer a vague question.
To be clearer what you need is a gene that will code for the protein, and a translation system. You can try acellular all the way (mix of synthetic RNA and ribosomes with the right buffers and molecules) or more simply put your bioengineered gene in a host as bacteria. You need to choose a vector adapted to your host (bacteria here, but could be eukaryotic cell). A way to select the cells that have your gene is usefull too 🙂
