Explain how to access tree guides and XSD

[racke]

Please check the following information and add it to the documentation:

uk: help -> Manage inventory -> Reference -> Tree Guides.

de: Hilfe -> Verwalten des Lagerbestands -> Weitere Informationen
Textdateivorlagen: Lagerbestandsdateivorlagen

es:
Seller Central Help : Manage Inventory: Reference: Browse Tree Guides (BTG)

XSD:
Hilfe -> XML Automatisierung: Weitere Informationen -> XSDs
Help -> View all help topics -> XML & Data Exchange-> XSDs