Hi Marten! In step 5 of the tutorial you'll find you'll need to create this directory. In particular you'll need to create directories such as "src\main\resources\assets\examplemod\textures\blocks” and “src\main\resources\assets\examplemod\lang\” to put your files in.

Also note that it's important to create these directories from inside Eclipse (rather than trying to create them in the Windows File Explorer) this will ensure that the directory is both created properly and recognized by your Eclipse project.