add temp check guide

[forcodedancing]

Add section about delegate/undelegate:

• Delegate: open https://snapshot.org/#/delegate/bnbchain-dao.eth, input the delegatee address, click confirm button, the wallet will ask user to sign and send transaction to bsc
• Undelegate: open https://snapshot.org/#/delegate/bnbchain-dao.eth, find the current delegatees in Top delegates and click the 'x' to undelegate of a delegatee, the wallet will ask user to sign and send transaction to bsc