download
https://www.raspberrypi.org/downloads/raspbian/

verify sha256sum

52e68130c152895905abe66279dd9feaa68091ba55619f5b900f2ebed381427b  2017-08-16-raspbian-stretch-lite.zip
b6bffeb28e11d45f26cb0463d124d3429d527005a9b577aab36a51ad6f4d942c  2017-08-16-raspbian-stretch-lite.zip.torrent
309f355ad5ca3e15d4866dfa16f17e4a5412632fec00976fe270d59516668849  2017-08-16-raspbian-stretch.zip
84e5951d0c2867f878778a52feb667b28b6a2bed80e68d30ffb00d6818795ef9  2017-08-16-raspbian-stretch.zip.torrent

flash sd card

dd if=2017-08-16-raspbian-stretch.img of=/dev/mmblk0 bs=1M

configure raspbian

sudo raspi-config

enable ssh, spi, serial, 1-wire, …