When you need your audience to look at different documents (files, videos, etc.) during your webcast presentation you need to make sure that each document is easily identifiable. You should avoid that it is going to be a puzzle for your audience to find the correct document that you need them to open during different parts of your webcast presentation.
During a live presentation when you have your audience in front of you, it is easier to directly see what they are using. This is different with a webcast. To avoid confusion, use not only a good identifiable name of each document but also give the document a reference number at the beginning (1, 2, 3, or A, B, C). Do not use the same reference number twice. By means of this you can easily refer to a document number during your webcast presentation.