How to get VAT refund in Spain?

Could you kindly elaborate on the process of obtaining a VAT refund in Spain? I'm particularly interested in understanding the requirements and documents needed to initiate the refund application. Additionally, I would appreciate it if you could clarify the steps involved in submitting the application and the typical timeframe for receiving the refund. Furthermore, are there any specific scenarios or conditions that may affect my eligibility for a VAT refund in Spain? Lastly, could you provide any advice on how to ensure a smooth and successful VAT refund process? Thank you for your assistance.