diff --git a/docs/companies/customer.md b/docs/companies/customer.md
new file mode 100644
index 0000000..cd98529
--- /dev/null
+++ b/docs/companies/customer.md
@@ -0,0 +1,19 @@
+---
+title: Customers
+---
+
+## Customers
+
+A customer is a client who parts are sold to.
+
+To access the customer page, click on the "Sell" navigation tab and click on "Customers" option in the dropdown list.
+
+### Add Customer
+
+!!! missing "TODO"
+	This section requires further work
+
+### Edit Customer
+
+!!! missing "TODO"
+	This section requires further work
diff --git a/docs/companies/manufacturer.md b/docs/companies/manufacturer.md
new file mode 100644
index 0000000..8e2ef45
--- /dev/null
+++ b/docs/companies/manufacturer.md
@@ -0,0 +1,33 @@
+---
+title: Manufacturers
+---
+
+## Manufacturers
+
+A supplier is an external vendor of parts and raw materials.
+
+To access the supplier page, click on the "Buy" navigation tab and click on "Manufacturers" option in the dropdown list.
+
+### Add Manufacturer
+
+!!! missing "TODO"
+	This section requires further work
+
+### Edit Manufacturer
+
+!!! missing "TODO"
+	This section requires further work
+
+## Manufacturer Parts
+
+Manufacturer parts are linked to a manufacturer and supplier part: they are the "items" sold by a supplier.
+
+### Add Manufacturer Part
+
+!!! missing "TODO"
+	This section requires further work
+
+### Edit Manufacturer Part
+
+!!! missing "TODO"
+	This section requires further work
diff --git a/docs/buy/po.md b/docs/companies/po.md
similarity index 100%
rename from docs/buy/po.md
rename to docs/companies/po.md
diff --git a/docs/buy/supplier.md b/docs/companies/so.md
similarity index 52%
rename from docs/buy/supplier.md
rename to docs/companies/so.md
index 454802e..bc9f5c9 100644
--- a/docs/buy/supplier.md
+++ b/docs/companies/so.md
@@ -1,15 +1,13 @@
 ---
-title: Suppliers
+title: Sales Order
 ---
 
-## Suppliers
-
-A supplier is an external vendor of parts and raw materials.
+## Sales Orders
 
 !!! missing "TODO"
 	This section requires further work
 
-## Supplier Parts
+## Line Items
 
 !!! missing "TODO"
 	This section requires further work
diff --git a/docs/companies/supplier.md b/docs/companies/supplier.md
new file mode 100644
index 0000000..1e0985c
--- /dev/null
+++ b/docs/companies/supplier.md
@@ -0,0 +1,35 @@
+---
+title: Suppliers
+---
+
+## Suppliers
+
+A supplier is an external vendor of parts and raw materials.
+
+To access the supplier page, click on the "Buy" navigation tab and click on "Suppliers" option in the dropdown list.
+
+### Add Supplier
+
+Once the supplier page is loaded, click on the "New Supplier" button: the "Create new Supplier" form opens. Fill-in the supplier informations (`Company name` and `Company description` are required) and click on "Submit".
+
+!!! note "Supplier vs Manufacturer"
+	In the case the supplier is a manufacturer who sells directly to customers, you may want to enable the checkbox `is manufacturer` before submitting the form (you can also enable it later on).
+
+### Edit Supplier
+
+!!! missing "TODO"
+	This section requires further work
+
+## Supplier Parts
+
+Supplier parts are linked to a supplier and defined as purchasable items.
+
+### Add Supplier Part
+
+!!! missing "TODO"
+	This section requires further work
+
+### Edit Supplier Part
+
+!!! missing "TODO"
+	This section requires further work
diff --git a/mkdocs.yml b/mkdocs.yml
index d08af7a..5793753 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -52,9 +52,12 @@ nav:
   - Build:
     - Build Parts: build/build.md
     - Bill of Materials (BOM): build/bom.md
-  - Buy:
-    - Suppliers: buy/supplier.md
-    - Purchase Orders: buy/po.md
+  - Companies:
+    - Suppliers: companies/supplier.md
+    - Manufacturers: companies/manufacturer.md
+    - Customers: companies/customer.md
+    - Purchase Orders: companies/po.md
+    - Sales Orders: companies/so.md
   - Report:
     - Labels: report/labels.md
     - Templates: report/report.md