If you provide more details about GT Designer 3, I might offer a more precise guide.
You're looking for a download link for GT Designer 3, specifically version 1.280s, in high quality.
File Size : 90.3 MB
20-08-2018
Avengers Box Qualcomm Module v0.12.4 Update Released - [20/08/2018]
Added: PLEASE NOTE YOU MUST UNINSTALL OLD VERSION BEFORE USING NEW
