[ADD] inventory: How to make the initial inventory?

https://docs.google.com/document/d/1YLqUpa3N6jTXvsL-53Y0P1awN5dLtMReKY1MQ_DhZek/edit#heading=h.z1h9s5nd8ghi

inventory/management.rst

@@ -6,4 +6,5 @@ Warehouse Management
    :titlesonly:
    :glob:
 
+   management/adjustment
    management/miscellaneous

inventory/management/adjustment.rst

@@ -0,0 +1,9 @@
+====================
+Inventory Adjustment
+====================
+
+.. toctree::
+   :titlesonly:
+   :glob:
+
+   adjustment/initial_inventory

inventory/management/adjustment/initial_inventory.rst

@@ -0,0 +1,108 @@
+==================================
+How to make the initial inventory?
+==================================
+
+One of the most important feature in an warehouse management software is
+to keep the inventory right.
+
+Once your products have been defined, it is time to make your initial
+inventory. You will reflect reality by inventorying the right quantities
+in the right locations.
+
+Product Configuration
+=====================
+
+In the Inventory module, open the :menuselection:`Inventory Control --> Products`,
+then click on **Create** to create a new product. Configure the
+product type so that it is **Stockable** and not a consumable.
+
+.. image:: media/initial01.png
+   :align: center
+
+Start the initial inventory
+===========================
+
+Update the product quantity for one product
+-------------------------------------------
+
+In the product you just created, you can see in the upper tiles that we
+have 0 product On Hand. Click on the **Update qty on Hand** button.
+
+A new window opens. In the **New Quantity on Hand** field, type the
+quantity of product you currently hold in stock, then click on **Apply**.
+
+.. image:: media/initial02.png
+   :align: center
+
+.. tip::
+
+	if you are using multiple locations for your warehouse, you will
+	be able to set the location of your product from this screen.
+
+You can now see from the On Hand tab that the quantity has been updated.
+
+.. image:: media/initial03.png
+   :align: center
+
+Now, if you check the **Inventory Adjustments** in the **Inventory Control**
+menu, you will see that a new line named "INV: (name of your product)" has
+automatically been created and validated by the system.
+
+.. image:: media/initial04.png
+   :align: center
+
+Multiple products at once
+-------------------------
+
+Create all the products for which you want to follow the stock (as
+stockable products). Once the required products in stock have been
+defined, use an initial inventory operation to put the current
+quantities into the system by location. Go to :menuselection:`Inventory Control -->
+Inventory Adjustments` to start your initial inventory.
+
+Give it a name (for example Initial Inventory) and select the stock
+location of your inventory. Note that when you select a parent location
+(such as Stock, which might be split into sub locations), you can also
+select the sub (or child) locations.
+
+.. image:: media/initial05.png
+   :align: center
+
+You can choose between making an inventory for all products, for a few
+or only for one. In this case, we choose the **All products** option.
+
+.. image:: media/initial06.png
+   :align: center
+
+.. tip::
+
+	If you need your stock valuation to be done in a different period
+	than the one that will be selected by default according to the inventory
+	end date, enter the corresponding accounting period in the Force
+	Valuation Period field. The accounting module needs to be installed.
+
+Click the **Start Inventory** button. Depending on the type of inventory you
+have chosen (all products or selected ones) you might have to add
+products manually by clicking on **Add an item**.
+
+Add the **Real Quantity** that you have in your stock for each product.
+
+.. tip::
+
+	additional information will be available according to the options
+	you activated (multi-locations, serial number, consignee stocks).
+
+.. image:: media/initial07.png
+   :align: center
+
+Click the **Validate Inventory** button to confirm the inventory and post
+it.
+
+Reporting
+=========
+
+To check the current stock, go to :menuselection:`Inventory Control --> Products`,
+and click on the **list button**:
+
+.. image:: media/initial08.png
+   :align: center