When tu watching some episide where tu can understand episode's name?

It would be easier to answer your pregunta if your pregunta was asked in a way that made más sense...

If tu are asking how to find the name of an episode tu are watching, the best way is to find it in an episode lista (if the name isn't enough for tu to be able to tell if it was the one tu were watching, then use a website that includes episode descriptions).

If tu are asking how to understand why an episode is named what it is named, the only answer I have is to try to figure it out based on the content of the episode