Hey Prateek — satoshi was basically mining by himself at the beginning. The late Hal Finney was the first recipient of a btc transaction (sometimes speculated to be a prime candidate for Satoshi / along with with Nick Szabo). See below for an interesting account. Glad the post helped!

https://www.washingtonpost.com/news/the-switch/wp/2014/01/03/hal-finney-received-the-first-bitcoin-transaction-heres-how-he-describes-it/