...
-decide version of the product, $VERSION (e.g. 9.0-rc1, 9.0-beta, 9.0vc1, for voting candidate 1, etc.)
-go to:
https://builds.apache.org/view/Incubator%20Projects/job/incubator-netbeans-release/
-press "Build with Parameters", fill $VERSION into the VERSION input line, press Build
-wait for the build to finish
-click on the build that was started above,
-download the build artifacts
-check the MD5 and SHA1 sums of each zip ($ZIP):
md5sum --check $ZIP.md5
sha1sum --check $ZIP.sha1
E.g.:
...