Another option, if you are using an animation, like “Set Size MyRectangle to 90 x Height linear 1000 ms” is to add a “Wait 1000 ms” then your other actions.
Or, if you’re trying to build in some intelligence to the progress bar—maybe some condition or event can interrupt or pause it—you could build a looping function to increase the width by a small amount—maybe 10 px or 5% increment, which you could then test the width at each loop iteration with a conditional case. Using a separate dynamic panel for the timer loop is the best method. It needs at least two states, set it to change states, Next, wrap, repeat N ms. Put a conditional case like Joseph shows above on the timer panel’s Panel State Changed event.