I don't know where to start with my custom character idea

[BuilderBob25620 (BuilderBob)]

To create a custom character from scratch check out these articles:

The process of rigging a custom character

Notes This topic is not for mesh/bone rigs. I will not be showing how to animate. I will only be showing you how to create/rig the character, and how to setup the Roblox animation plugin with your character. Intro Hello everyone! Today I will be showing you how to create and rig a custom character. I will not be showing how to use the animation plugin or using animation plugins with this as that is not the point of this tutorial. Resources I will only show the process of rigging with …

https://education.roblox.com/en-us/resources/education/arcade/customCharacter

They will help you understand the actual character model works and how to rig your character.

EDIT: Thanks to @ULTR4ST0RM for the updated article link.