Reverse transcription (RT) is used to make DNA copies of RNA. PCR can then be used amplify specific DNA from the sample. Amplify here means to make a ton of copies so you from one DNA molecule to a bajillion of the same molecule.
Biologists use this technique to study RNA expression. Hope that makes some amount of sense. In the comic he was more or less outlining the steps needed to carry out the technique which involves mixing stuff together and then heating the reaction mixture to different temperatures
Wiki link if you wanna go down the rabbit hole:
https://en.wikipedia.org/wiki/Reverse_transcription_polymerase_chain_reaction
U take a micro piece of dna and replicate it multiple times until it becomes a length thats large enough for u to study /research or zoom into. Rna and dna are different in the sense of rna is smth that codes for proteins but its a single structure while dna is double structure. He outlined the steps to turn rna into a dna and then replicate that dna multiple times

The pcr bit was so funny. I love when the author leans into the biology stuff
Also great job translator! You got the terms right!