How to create a ladder / vine

Hi! I was creating my mod and I need a little help to finish: how would I go about creating a ladder in MCreator? I read some topics about it and a suggested idea would be to copy the code from the block and then modify it my way, but how do I do it? I tried to check in %appdata% -> .minecraft, but I don't know much about programming languages and I can't find anything. If you can help me with the creation of the ladder or a tutorial on how to find the codes of the blocks in the Minecraft source code I thank you !!!