You can easily implement a series-picker UI using the chart's series property, a ListBox control, and Wijmo's showPopup and hidePopup methods.
For example, the chart below starts with an auto-generated set of series. Click the gear icon at the top-left corner to show a ListBox where you can select the series you want to display.
Note that you can achieve a similar result by setting the chart's legendToggle property to true. Once you do that, the legend itself acts as a series picker: clicking any series name in the legend toggles its visibility.