how to copy and paste in ubuntu

i this a basic question
i am very new to qiime2
so please help me
while using ubuntu i cannot copy and paste the command
and i am also double clicking and its not working what to do for copy and pasting

Hello!
Welcome to the forum!

If you mean in the terminal window, then it is ctrl + shift + c or v, and outside of the terminal, it is ctrl +c or v

Here is the link to the basic tutorial.