The first thing which comes to one’s mind eventually is how to copy the base design, especially that one, which you couldn’t break or the one from the league ladder top.
So, there are different ways to copy other player’s base.
Join the clan where the desired base could be copied easily from other player’s profile. As soon as you join the clan, the problem doesn’t exist. But remember to have the same town hall level or only 1 level lower/higher, otherwise you won’t be able to reproduce the layout directly.
Manually. Make a screenshot of the desired base and try to reproduce traps locations. If you have replay – that’s better, you can slow it to 1/2 of speed and notice all the traps.
Find on the internet or on cocthegame.com website similar or better one, click “download” button. This button will redirect you to Clash of clans official website, which will open the game on your device and offer you to put new layout into available slot.