The participants are able to respond to the survey until you have closed the questionnaire for answering. This means that even if the deadline has arrived, it is actually still possible to answer. To stop that, you have to click on "Close questionnaire for answering."
When the questionnaire is closed, it moves from "ongoing" list to the "closed" list. If for any reason it should be necessary to re-open the form, you can do that - just press the button "Open for answering."
Choose the tab "Overall answers" to download the results in Excel format.
Here you can also edit the answers. Generally, there is no need to do this, but it may be necessary, if someone has been, for example, too rude on their comments. After editing you can still show the original comment.
You can also leave out a response / rating - just untick it.
If you'd like to write your own summary to the evaluated person, you can do that at the end of the questionnaire.