Creating layers

To create new layers, click on the Add New Layer icon in the Layer Properties Management dialog. Now a new layer is created with default settings and the name 'Layer n'. New layers can only be created if all the layers are visible.

It is also possible to create standard layer names in ARCHLine.XP. Check Protocol for Layer Naming at the bottom of the Layer Property Management dialog, and then click on the Add New Layer icon. A new dialog box opens in which you can enter the layer names using letters.

More about layer protocols: 

AEC (UK) Protocol for Layer Naming

The AUEC (UK) Protocol for Layer Naming provides five fields separated by a hyphen, to classify a layer based on the conventions outlined in BS1192:2007 for container naming within a file. It provides a unique reference to a logical collection of elements.

https://aecuk.files.wordpress.com/2016/01/aecukprotocolforlayernaming-v4-0-2.pdf

US Layer name format

"The layer name format is organized as a hierarchy. This arrangement allows users to select from a number of options for naming layers according to the level of detailed information desired. Layer names consist of distinct data fields separated from one another by dashes. A detailed list of abbreviations, or field codes, is prescribed to define the content of layers. Most field codes are mnemonic English abbreviations of construction terminology that are easy to remember.
There are four defined layer name data fields: Discipline Designator, Major Group, two Minor Groups,
and Status. The Discipline Designator and Major Group fields are mandatory. The Minor Group and Status fields are optional. Each data field is separated from adjacent fields by a dash ("-") for clarity."

https://www.nationalcadstandard.org/ncs6/pdfs/ncs6_clg_lnf.pdf