According to your account, opening a restaurant of the scale you mentioned generally requires an investment of about 1.2 million yuan. As for the documents needed for business, you should first apply for a health certificate and a health permit at the health and epidemic prevention station where you are located, and then apply for a self-employed business license at the Industrial and Commercial Bureau with the house lease contract of your business place. After obtaining the business license, you should apply for the tax registration certificate at the local tax bureau. Generally, it takes one and a half months to process these documents, and the cost is around 500 yuan (in different places).