KiCAD ver 5.1.4 to Altium AD19.0.8

Assuming you have KiCAD source files.

KiCAD > File > Fabrication Outputs > Drill

Precision 2,4

KiCAD > Plot Gerbers

Use Protel filename extensions.

Altium > New > CAM Doc (Camtastic)

File > Import > Drill. . .

Units. . .

Tool Table. . . 

Define Tool Table (Drill sizes)

Tables > Layers, set Top to Top and set Drill to Drill Int.
Tables > Layers Order > Set Physical Layers

File > Import > Gerber
Place > Flash
Tools > Netlist > Extract > Wait for it . . . 

File > Export to PCB

That's it !

Importing xDxDesigner Schematics

xDxDesigner is  the schematic capture tool for Mentor Graphics Xpedition.

In altium the xDX Designer Importer extension (a Software Extension) can be found on the Purchased tab of the Extensions & Updates view (DXP » Extensions and Updates).

See: xDX Designer Importer | Online Documentation for Altium Products

Correct folder structure is important !

You may need to arrange the folders and files before importing xDxDesigner files.

See: Importing Dx Designer schematic to AD - Altium Discussion Forums

That's it !

Rework Queries

(ObjectKind = 'Track') And OnSignal And (Net = 'No Net')

(ObjectKind = 'Track') and OnSignal and HasViolations


Find Dead Vias, Tracks and Arcs

(((((ObjectKind = 'Track') OR (ObjectKind = 'Arc')) And OnSignal)) Or IsVia) And NOT InAnyNet And Not InAnyComponent And NOT (Keepout = 'True')

Get Size From Sheet Layer

To Set the Sheet Size in the PCB Editor.

Assign a Mechanical Layer Type to Sheet

Select the Mechanical Layer > Properties > Other > Get Size From Sheet Layer

Tip: You can set the Layer Type back to N/A after using Get Size From Sheet Layer

That's it !