Design a cohesive series of videos with consistent branding, structured hooks, and clear calls to action across every episode.
Yes — always include the part number. It tells new viewers where to start and tells returning viewers where they left off. "Part 3" also creates curiosity about Parts 1 and 2.
End every episode by explicitly teasing the next one. "In Part 4, I'll show you exactly how to..." creates a cliffhanger that makes viewers subscribe and return.
That's common and expected. Always include a brief "this is part X of Y series" at the start, and link to the full playlist in your description and pinned comment.