If you want to use WebStorage you need to save your data to it and then - read it.
To save data to WebStorage use Set local value action. Use any key and store you Timer value (example, key: "finish_time" value: Timer).
Any time you want read it with WebStorage.LocalValue(key) expression.
Our example: Text.SetText -> WebStorage.LocalValue("finish_time")
You'll take your last Timer value.
It will be still there even if you close your browser and open it again.