The Record Temperature Task in Polus is a short simple task. All you have to do is match the temperature number on the left Log screen the same as the number on the right Reading screen. Adjust the temperature by clicking/holding the arrows to increase or decrease the number that is currently displayed.
There are 2 versions of this task, one located in the Laboratory room, where you have to lower the number. The second one is located in the exterior and here you have to instead increase the number.