Hey Zsi48891,
Just like andheum mentioned, you just need to use a regular slider connected to a “evaluate curve”-component ( the curve has to be reparametrized (right-click on the input curve and select reparametrize to set the domain of the curve to 0 to 1 )).
With the UI components, you can change the slider and the point on your curve.
greetings,
Bumaye