To add medicine stock you should enter purchased medicine details, for this click on Purchase button here you can see list of purchased medicines.

To add purchased medicine details click + Purchase Medicine button now here enter Supplier name, Purchase Date, Medicine Category, Medicine Name, Batch No, Expiry Date, MRP($), Batch Amt, Sale Price($), Packing Qty, Quantity, Purchase Price($), Amount($), Note, Attach document, Discount, Tax. After filling all relevant details, click on calculate button then final amount will be calculated then click on Save button.