Our first timestamp of the musical is in 1776, where Hamilton meets Aaron Burr in New York. Throughout the course of the play and Hamilton's life, Burr plays a vital role and is sort of like the polar opposite of Hamilton.
When they first meet, Hamilton admires Burr greatly as we can see from the line "I wanted to do what you did, graduate in two [years], then join the revolution". Hamilton finds many commonalities between him and Burr, as they are both patriots and orphans looking to climb up the ranks and gain a reputation. However, their views and beliefs differ greatly and as time passes tension starts to build between them.
First interaction between Hamilton and Burr in the musical Hamilton
One of Burr's catchphrases, which is introduced in this song, is "Talk less/Smile more". America at that time wasn't fully pro-independence, and many independence supporters (also called patriots) could get punished by loyalists (colonists who supported the crown) or by British soldiers, as seen in the line "fools who run their mouth off wind up dead". Burr is a very careful person who likes to hide his intentions and beliefs, while Hamilton is very proud and likes to openly announce his views on independence.
Towards the middle of the song we are introduced to John Laurens, Lafayette, and Hercules Mulligan, who are discussing revolutionary beliefs in a pub. In this song they are all Burr's friends, but over time they start to grow closer to Hamilton because they are all proud of their identities as patriots, rather than hiding it for their safety like Burr does.