This will allow you to admit participants one at a time into your virtual office. You can then work with one student at a time during office hours. 

First, enable the waiting room option in your settings.

When scheduling a zoom meeting, check the waiting room option.

Now when your meeting is in progress, students will see the following when they are waiting:

Admitting participants during a meeting

As the meeting host, click Manage Participants.

Click Admit to have the participant join the meeting. You will do this for each participant you'd admit into the meeting. So ideally, once you have worked with one student and they have left the room, you would then admit the next.

Customizing the Waiting Room

You can customize the waiting room title, logo, and description at an account, group, or user level.

Note: You will need to enable the waiting room before you have the option to customize it.

After enabling the waiting room, navigate to the Waiting Room option under In Meeting(Advanced).

Click the pencil icon below the Waiting Room option.

This will open the waiting room customization options.