Especially as the program comes with only two scenes and four characters. If you think this sounds limiting, then you're right.
You'll start by choosing the scene (a classroom, maybe the water cooler), then add the characters, enter some dialog, customise this with an action or emotion (afraid, bored, facepalm), perhaps add an animated action on its own (handshake, kiss, slap).
There's no need for any animation experience, as your movie is built entirely from Plotagon's own 3D library. Plotagon is a free tool which makes it easy to create simple 3D animated videos.