The WebStorage object uses a very simple storage model: values are stored under named keys, similar to how the Dictionary object works. For example, the value 100 could be stored for the key score with the action Set local value "score" to 100. Similarly the value John can be stored for the key name. Then the expression WebStorage.LocalValue("score") returns "100" (as a string) and WebStorage.LocalValue("name") returns "John", and these values persist between sessions. (If session storage was used instead, the values would only last as long as the browser session.)
Note WebStorage only stores strings. If you set a key to a number like 100, when you retrieve it back it will be a string. To convert it back, use the system expression int, e.g. int(WebStorage.LocalValue("score")).