Fine Points

Use \footnote{footnote-text} to add a footnote
Use \{ and \} to output the actual characters {, }
In math mode, use \big(, \Big(, \bigg(, \Bigg( for larger-sized left parentheses – also works for ), [, ], \{, \}, etc.
In math mode, use \text{plain-text} to include plain-text in standard, non-math format
Use the character ~ for an unbreakable space
And many more...

Use \footnote{footnote-text} to add a footnote