For more information, see Text Parser in the Make Help Center:
Match Pattern
The Match pattern module enables you to find and extract string elements matching a search pattern from a given text. The search pattern is a regular expression (aka regex or regexp), which is a sequence of characters in which each character is either a metacharacter, having a special meaning, or a regular character that has a literal meaning.
For experimenting with regular expressions, we recommend the regular expressions 101 website. Just make sure to tick the ECMAScript (JavaScript) FLAVOR in the left panel.