Your phone must be hacked in order to this
You will need to download:
X-plore
Hello Carbide
Install Server Os9.1

Now install X-plore.
Then install Hello Carbide to PHONE MEMORY.
Run X-plore, press 0 and tick all four boxes.
DO NOT CLOSE X-plore.
Press menu key and go to Applications folder.
Run HelloCarbide press Options: Menu1: now keep clicking Yes until the app closes.
Ok now press and hold menu key and choose X-plore.
Find and open the Install Server Os9.1.zip and highlight the installserver.exe press 4 on key pad then navigate to c:sys/bin/
Highlight the bin folder and press centre key to copy installserver.exe there.
You need to restart your phone.
Now you can install any 'Unsigned' app without signing.