what does 'target 1' and 'target 2' in ettercap represent for?

To start the attack, we need to specify target 1 and target 2. As the first target, you need to specify the IP of the machine that we are going to attack, and the target 2 is the ip of the router.^[1]

我不晓得为什么很多中文文章是反着来的, 按照中文的反着来我无法成功.