I referred below blog to download trail version of manufacturing apps.(In download section, 2nd option)
Can I install Trail version of Manufacturing apps in a server machine where Thingworx 8 is already installed?
Does it creates any issue to existing licensed version of Thingworx 8?
You can download them as extension from support.ptc.com under Smart Connected Operations. You will require the license though. Alternatively you can shutdown your Thingworx Server 8 which you have and install the express version in different location. I prefer the extension approach.