I'm considering purchasing an adapter so I can use my touchscreen connected to the GPIO pins, and my PiGlow at the same time. I've seen one supplied by Geekroo on ebay which is unassembled, my question is, how would this need to be assembled and is there another way to be able to increase the number of GPIO pins to be able to use both HATs?!
To assemble the board you would need to solder the pins to the board.
Using multiple hats (expansion boards) at once may not always be possible because of issues with pin assignments. Some pins and interfaces can support multiple devices on a particular pin (e.g. I2C), others cannot. I2C is what the Piglow uses, as can be seen here. You don't mention which touchscreen you have, so I can't be sure, but you likely can get these to work together. Power issues can be another source of problems. Obviously, the more devices you connect the higher the current requirements will be (assuming the boards are powered via the GPIO pins). For some combinations the Pi may not be able to supply enough power.
Depending on the boards you may be able to use stacking headers (though this will reuire soldering - and will not work in your case as both boards need to be visible.
Assuming there are no pin conflicts, you could create your own board to breakout the pins to both expansion boards. If you can't solder (learning is not difficult). You could do it with a breadboard and jumper wires. While not as permanent as a soldered connection it will work. Something like the Pi T-Cobbler can make this easier. Once you get this working and have learned to solder you can make it more permanent using a prototype board like this one; it works just like a breadboard. I have linked to the Adafruit store, but similar items are available from Ebay, China and other resellers.