The process of setting the coordinate system from points in a point mesh is generally the same as in Setting Multi-point Transform. However, imported point clouds and meshes can be quite dense compared to low-count point files typically used for coordinate setup:
To facilitate the assignment of individual points in the point cloud the above view will appear and you first need to select and create individual key points from the point cloud. First select a point in the point cloud that corresponds as closely as possible to a 3D point in your project (you may need to zoom in), then click the "Create transform point" button at top. Each time you do this the point will enlarge in the viewer and its coordinates will be added to the table below the viewer:
When assigning the point to an existing 3D point in your project, use the selected point in the table and follow the typical assignment process.
You can create the transform point and assign it at once by pressing the Assign button while a 3D point in your project is selected and a point is highlighted in the mesh.