For example, if I have 40 photos on my SD card but only want to import 10, which setting in the Lightroom Import window allows me to filter the view so that only the selected photos are shown, hiding the remaining 30?

There’s no way to filter photo visibility in Import, but there is a Sort menu at the bottom. If you sort by Checked State, then all of the photos currently selected for import will group together at the top or bottom depending on the sort order you set.

One thing to watch out for are the different ways images get marked for selection. In the video that Rob_Cullen posted, about a minute and a half in you can see images that are highlighted, checked (ticked), or both. What you want to pay attention to are the check boxes. If an image’s check box is enabled, it’s going to import; that’s what makes the Checked State sort order useful. The highlights are used for other purposes, such as setting up images to be checked.

There are no “filters” in the Import dialog box. But in the Import dialog box, you can click on “Uncheck All” and then click the box on the 10 photos you want to import.

PS: when you create a message in this forum, the first dialog box you type into requests that you BRIEFLY describe your question, like “Filtering before importing”. The next dialog box is where you type your full detailed question.