update README

README.md

@@ -63,8 +63,25 @@ You can override the default product options using WHMCS Configurable Options:
 1. Go to **Setup > Products/Services > Configurable Options**
 2. Create a new group and link it to your VPSAG product(s)
 3. Add options with these exact names:
-   - `planid` - To allow customers to select different plans
-   - `osid` - To allow customers to select their OS during order
+   - `planid|Plan` - To allow customers to select different plans
+   - `osid|Operating System` - To allow customers to select their OS during order
+
+**Option format:** `{api_id}|{display_name}`
+
+The numeric ID before the pipe is the API ID from VPSAG/EVPS.
+
+#### Finding the IDs
+
+The easiest way to find the IDs is through WHMCS itself:
+
+1. Go to **Setup > Products/Services > Products/Services**
+2. Edit any product using the ArkhostVPSAG module
+3. Go to the **Module Settings** tab
+4. The **Plan** and **Operating System** dropdowns show all available options with their IDs
+
+The dropdown values are the IDs you need. Simply use those same IDs when creating Configurable Options.
+
+**Note:** OS availability varies by plan - you must select a Plan first before the OS dropdown populates.
 
 The module checks for configurable options first, then falls back to product-level settings.