Where can I find the extensions folder?

Where can I find the "extensions" folder?
I am looking for him and he is nowhere to be found.

There hasn't been an extension folder for a while. Extensions are stored with other dependencies inside the vendor folder.

And where exactly to put the extension if I want to upload it manually?

Have a look here for extensions written by yourself:

Somewhat outdated in some details, but it describes the use of the workbench folder well:

Have a look at the extension tag. Each extension should com with instructions how to install it.

If you want to write extensions yourself, have a look at my post here: Pollux

Mezir check out the links shared by Pollux ?

I'm trying to do it according to this guide: http://flarum.org/docs/extend/start/

Just tell me where the "extensions" folder is or where to create it.

Mezir I'm trying to do it according to this guide: http://flarum.org/docs/extend/start/

This guide is outdated.

Which guide is current?