Layouts are mandatory for local repositories since they define the structure with which artifacts are stored.
To select a repository layout for a local repository:
In the Administration module, select Repositories.
Do one of the following:
When creating a new repository, click Create a Repository and then select Local.
or
When modifying an existing repository, click the Local tab, locate the relevant repository and click its repository key.
In the Basic tab, scroll down to the Repository Layout field. When you create a new repository, Artifactory will recommend the best layout according to the package type.
Select a repository layout from the list and then click Save.