add information to ERC-20 Guide

During the contract deployment, I encountered a number of problems. In order to make the guide simpler and more understandable, you need to:
1. Specify which version of Node.js is required.
2. In paragraph 8 and further, you need to specify in which directory the command should be executed.
3. Add which values ​​can be changed to change the name, attributes, and number of tokens.