@Mohammad_Nawar In the IN[0] you should connect a selected model curve from the revit model. First you draw a model line in the model, where you want to locate the dimension line and than you select it trough the Select Element node.
As for the dynamo node which is build in, here is a screen shot. You don’t need to install special package, you need only to download dynamo 1.2. That’s all. Hope this is enough = )
