If you learn the Braille alphabet, you've essentially learned uncontracted Braille, aka 'grade 1 Braille.' This type of Braille takes up a LOT of space on a page.
#ContractedBraille has contractions, short forms, word signs and so forth to let more words be conveyed in this #monosized, #monospaced print environment.
This link leads to a handy summary chart (but doesn't reflect all the additional rules that may apply):
https://www.duxburysystems.com/braillechart.asp
20/x