Regular Expressions: Restrict Possible Usernames {2,} help

https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/regular-expressions/restrict-possible-usernames

let userCheck = /^[a-z]{2,}\d*$/i;

where is the “{2,}” is explained before this challenge?
can someone help me understand where this is coming from?
the rest is clear to me…

ok i see.
i did the whole section again cause i thought i missed something…
thank you ill try in a different way