What is the best way to learn coding for mali t760?
You access the GPU via either OpenGL ES (graphics), or OpenCL or Renderscript (both for GPGPU compute) APIs. There is no means to write assembler directly for the GPU - your application provides source code which is compiled by the driver into an executable binary.
There are plenty of good tutorials on learning OpenGL ES or OpenCL on the web, including some over at http://malideveloper.arm.com.
HTH, Pete