Gr_modtool to add grc block

Hi every body,
I have activated gr_modtool and i have python code too, can anyone
explain to me step by step how to add my python file to grc as a block?

I made progress to add block with gr-modtool but its gave me errors like
make[2]: *** [lib/CMakeFiles/gnuradio-myQpsk.dir/] Error 1
make[1]: *** [lib/CMakeFiles/gnuradio-myQpsk.dir/all] Error 2
make: *** [all] Error 2

so what should i do?