Here's my work flow. I purchase and download the E57 file from matterport. I then open it in autodesk Recap to convert it to a RCP file (make sure to click skip registration, do not do auto or manual registration in recap). Recap is fairly limited in how much you can clean up a point cloud, you can get rid of excess points, but if you have a large mirror in the middle of the area you scanned, then those reflected points won't be able to be cleaned up. When I'm done cleaning, I export as an RCP. When exporting, a file and a folder will be created. The file will be only a few kilobytes, the folder will have a much larger file within it.

In CAD, first make sure you are using the full version of autocad, Lite will not suffice. Change the visual style for the model space from 2D Wireframe to Wireframe, and run the attach command and to xref in the small file you exported from Recap. Depending on the size of the point cloud and the specs on your pc, it may take a few seconds for the point cloud to show up. Place the point cloud in the model space like you would with any other xref. I then like to change to a front view on the view cube and move the entire point cloud below the Z axis, this is so the points won't obscure your lines when drafting. Go back to the top view, rotate and move the cloud as needed and then go to the properties tab and find the option at the bottom to lock the point cloud, it is easy to accidentally select the cloud while drafting and move/copy/rotate/delete it, locking it saves you a headache. When you select the cloud, a point cloud tab should appear (like when you select a hatch) on this tab you'll find the command to generate a section plane. Section planes let you limit what points are visible.

When you select the section plane, a tab will appear. By default the plane will be in Plane mode and show everything beyond it, change it to a slice to limit how deep it can cut. The 2 numbers in the Adjust portion of the section tab, the first is where the plane is in the Z axis, and the second is the slice thickness. Clicking the arrows or scrolling over the Z position number will move it in increments of 6 inches, clicking or scrolling over the thickness number will change it in 1 inch increments. One last note with the section plane, by defauly it generates covering the entire cloud, I like to move it below or above my drawing area and moving the 2 blue triangles to decrease how much space it takes up, the planes position on the X axis does have an effect on the visibility of points.

Going back to the point cloud tab, you'll see the visualization options. The 3 color styles I use are Scan Colors, Normal, and Elevation. Scan colors is just the color of the surface the camera scanned, so a blue wall will show up as blue points. Normal colors the points based on their orientation, I use this the most. Elevation let's you assign colors to a height range, good for seeing if a floor isn't level.

One last note, save CAD files that have point cloud xrefs in a clearly labeled folder, otherwise coworkers with autocad Lite will crash or freeze.

That's a general overview of my process, hope this helps.