Ocr f215 help!!

I've been looking at genetically engineering insulin and I really don't get it! Could anyone explain it to me please?

Thank you!

Insulin is a polypeptide, 51 amino acids long

1) mRNA for the insulin gene is identified
2) Reverse Transcriptase enzyme synthesises a complementary DNA strand
3) Ribonuclease H removes mRNA strand, leaving DNA template strand
4) DNA Polymerase uses free nucleotides to create a complementary DNA strand from the template (cDNA)
5) Unpaired nucleotides added at each end to make sticky ends
6) Plasmids (loops of DNA for antibiotic resistance in bacteria) are cut open with restriction enzymes
7) These are mixed with the cDNA and some plasmids take up a cDNA fragment
8) DNA Ligase enzyme seals the fragment into the plasmid with the sticky ends - RECOMBINANT PLASMIDS
9) Plasmids mixed with bacteria culture and some bacteria take up a recombinant plasmid
10) Altered bacteria cultured and colony produces insulin

Hope this helps