Generally the CTs will have 1 players on the site while the second players is playing towards CT or coffins. During the execute you should smoke off these parts so you can isolate thst 1 player on site.

As an entry you should focus on getting info or even the kill on the site player to secure the site and allow for a fast plant. Stopping and taking aim duells or waiting for peeks will delay your plant and give the CT rotations more time.

There are situations however where CTs play 2 on site. In this case it can make sense to push construction as the entry player to get a flank going on the site players or to get into a position to intercept the CT rotations. But this has to be communicated and planned with your team or your tram will get in trouble, when they take on the site players on their own, while you are on another mission.