Electronic – Edit a silkscreen over a gerber file in Altium

I have downloaded the design you are dealing with. The gerber files, all layer files have .PHO extension.

Import gerbers into Altium

If you rename the files as follows you will be able to open them in Altium:

• Layer4.pho \$ \longrightarrow \$ Layer4.GBL, this is the bottom layer
• Layer1.pho \$ \longrightarrow \$ Layer1.GTL, this is the top layer
• Layer2.pho \$ \longrightarrow \$ Layer2.GP1, GND plane 1
• Layer3.pho \$ \longrightarrow \$ Layer3.GP2, GND plane 2
• SoldermaskBottom.pho \$ \longrightarrow \$ SoldermaskBottom.GBS
• SoldermaskTop.pho \$ \longrightarrow \$ SoldermaskTop.GTS

I have identified the layers by the PDF appendix. For Pastemask (GBP, GBT) and Silkscreen layers you should search for their Altium extensions.

These modified files can be dragged and dropped into Altium, example for Top layer:

This way all layer files are easily openable in Altium.

Export TopLayer gerber into PCB document file

1. Select Layer1.GTL tab in Altium

2. Select the Menu → Tables → Layers Order option. Following dialog will be shown: Fill the cells as below.

   

3. Enable the Export to PCB option as follows: Menu → Tools → Netlist → Extract.

   "After a netlist has been extracted from your CAM data, the File » Export » Export to PCB command becomes enabled" source

4. Now, select Menu → File → Export → Export to PCB and a new PCB document will be opened with the Top Layer.

   Result:

   

First, you need to select the CAM Processor I am sure you will know already (Kinda looks like a camera in the toolbar - see image below)

And then it should open a screen the same or similar to the one below:

Now you can either add each layer manually, or Eagle does have some default Gerber generators that you can use. If you click on File->Open->Job, you can select either 'Gerber' or 'Gerber274x' (see images below).

If you create the layer yourself you just need to press 'Add' in the bottom right of the screen and give it a name that means something to you, and the correct extension (I assume you know this being a PCB house) but it typically is '.GBO' for the bottom silkscreen (gerber bottom overlay).
Then on the right hand side of the screen you need to select the layers that it will extract the Gerber from - in your case I imagine it will be something like 'bDocu' or 'bPlace' or 'bNames' or all of them. You might want to confirm with your client about this if you don't know, below is what it should look like.

Once you've done this, if you click on process job / process selection, it will create your Gerber file for you. This will be put in your project directory, and you can then view it using a Gerber viewer.