Scheduled meetings are usually meant for 1:1 calls. For every booking a unique video calling link for 2 participants is created and destroyed once the call is over. However there is a work-around if you want to add more people to a scheduled meeting.
1) Create a new meeting room under "Meeting Rooms" and copy the meeting link
2) Go to "Meeting Types", "Edit" the respective meeting type and select "Online meeting via an external tool" under "Location"
3) A "Link to an external tool" field will appear in which you can paste the meeting link from Step 1
4) Your client will now receive the meeting room link to join the call. This meeting room link can be shared with as many participants as indicated in your meeting room size.