With control points, you can manually create a link between two or among more images. Provided additional links, RealityCapture can estimate transformations among images or components.
There is not any component in the current project. You can continue, but it is better to create some components, so that you can follow this tutorial steps and learn how to merge components which belong together.
There is a single incomplete component in the current project. Add control points to merge components.
You already have a component containing all images. Congratulations!
Then simply click Align images (F6) in the ALIGNMENT tab and RealityCapture will do the rest.
The difference between a control point and a ground control point is a 3D coordinate assigned to the control point. RealityCapture application displays a geo-referencing icon next to such control points. You can geo-reference components with at least three control points. Accuracy is improved when more points are provided. Once components are geo-referenced, click Align images (F6) in the ALIGNMENT tab and RealityCapture will automatically try to improve accuracy by finding additional tie points.