hello i need help

Question = Create a Sequence Diagram detailing how a customer can buy cryptocurrency from start to finish. Identify actors, entities, and participants

NBank - the future bank

The team's task is to process NBank's written material and develop models that help clarify the business plan and requirements so that NBank can reach its funding goal and start developing "the future bank."

The bank will offer its customers standard and non-standard banking operations. Standard bank services include opening and using a checking account and a savings account, where both allow deposits and withdrawal. If they meet the requirements, the bank will also allow its customers to apply for an overdraft (sl. "yfirdrttur") on their checking accounts (Note: Not checking their accounts). Customers can apply for credit cards, virtual and physical, where virtual cards change the card number after every use to prevent fraudulent charges.

In addition to these "standard" bank service offering, customers can trade and sell various cryptocurrencies in their banking applications. The bank offers a fixed fee for conversions and maintains a competitive market for cryptocurrencies and NFTs (Non-fungible tokens).

Checking rules

• Checking accounts gather interest if the balance is > 0. Checking accounts can be closed if the balance is 0.
• Checking accounts can have an overdraft allowance or not.
• Checking accounts can always have money deposited.
• Checking accounts cannot go below balance 0 unless there is an overdraft associated with the account, in which case the customer can withdraw up to the overdraft allowance.
• Each customer can have up to three checking accounts.

Overdraft rules

• Customers can apply for an overdraft. The application needs review, done by a sophisticated algorithm.
  • The applicant must have been a customer for at least three months.
  • The applicant must have a steady income flowing into their account monthly (such as a paycheck). If these criteria are not met, the customer is notified, and the application is closed.
  • The overdraft cannot exceed more than a month's regular deposits. These applications automatically have their overdraft limit reduced to this number and approved if other criteria are met.
• The customer can only have one checking account with an overdraft.
• The customer pays interests of overdraft as it was a fixed loan with 15.5% compounded yearly interest.

Savings rules

• Two people can share their savings account, so the account is visible in both their internet banking applications. They are both owners and share all the same options for managing the account.
• Customers can choose to retain their money in the account for a fixed number of months for a higher interest rate. They can set the length to 3, 6, 9, 12, and 36 months. When the account is fixed, the customer cannot withdraw from the account until the time is up, and then it will open up for one month before closing again for the same amount of time as it was previously locked.
• Each customer can have up to 10 savings accounts.

Crypto trading example

• The customer has to activate the trading account, where they must accept terms & conditions and agree that the crypto trading is done with money earned legitimately. The customer must also register their crypto wallet address or create a new wallet in the internet banking app.
• The customer can view the crypto marketplace for current prices. Compare and view how the price has changed over a given period.
• If the customer wants, they can make a bid to purchase some amount of given cryptocurrency.
• The NBank crypto market receives the offer and starts communicating with other crypto marketplaces, requesting the amount of the given cryptocurrency for the price offered. The money is taken from the customer's bank account and placed in a trading account. The customer can see the trading account but is unable to make any transfers into or out of the trading account; it is a special type of account. Each customer has a single trading account, but they need to be activated manually in the internet banking app.
• NBank market automatically makes the purchase, in single or multiple transactions, depending on the amount being bought and the amount available to buy from each other market or seller. This happens automatically but can take some amount of time.
• Once the NBank market has gathered the requested amount, the trading account is emptied, and the crypto is transferred directly into the customer's crypto wallet.