thank you starchaser, for this clear and detailed explanation, i hope this information will help any other player who need the same mission, thanks again.
after succesfully done sm, i would like to share additional info: ennemy base marked area might change every time you accept the sm, we want ennemy base must be far away from our base; so if our base and ennemy base are close, just drop sm and restart, go orbit and accept; go again to our base and check where will be ennemy base; simply do this until ennemy base appear near lz and/or far away than our base; then keep mission. if ennemy has zero canisters, like "you 15, ennemy 0" just wait until pirate terrorizers bring new canisters, then collect.