Problem 1: lottery

1. Install Metamask
2. Restore accounts using Seed phase:
    income orchard else soldier spot dog eight business bulb obey swear budget
3. Open source code, run commands:
    npm install
    npm start
4. Interacting with DApp by metamask's accounts

Problem 2: voting

1. Open source code in folder voting-2.0
2. Run command:
    npm run deploy-contract
    npm run server

Problem 3: campaign

1. Open browser, access https://remix.ethereum.org/
2. Copy and paste source code to remix
3. Deploy contract
4. Interacting with DApp by metamask's accounts

Problem 4: car-trading-system

1. Open source code
2. Contract was deployed. If user want to deploy again, run command:
    npm run deploy-contract
3. Start server then access DApp at url: localhost:8008 by command:
    npm run server