Typical process is here (though not comprehensive):
Let me start with placing the PO
If advance payment is required to be made, then obtain pro forma invoice and make the payment through your bank
If the vendor has any tie up with any freight forwarder, then shipping from such freight forwarder is the best option as it is economical (otherwise you need to arrange it)
Arrange for insurance before the items are shipped (if needed)
Once shipment arrives customs in India, arrange for clearance by providing necessary documents to your CHA
Once the shipment is assessed, make payment of customs duty
After the clearance order from customs, the item would be delivered to you by your CHA probably.
If advance payment was not made, you need to make the payment to the vendor within 6 months (for capital goods 3 yrs)