1.Directly input your host (like: cgtn315.aliyun.com) into Host (don't input like http://cgtn315.aliyun.com).
And put login & pwd , then click
2.After that, will appear a tab named your Host, and may ask you input your account name and pwd again.
Note that, account can copy and putty will auto detect it and shown on screen. But pwd cannot copy, you should mannually input it.
3.Some linux frequent used command is here for your reference:
https://www.linuxtrainingacademy.com/linux-commands-cheat-sheet/ (may need VPN)
https://blog.youkuaiyun.com/u011144776/article/details/82220171