I am migrating my system to 64 bit and the debian wiki suggests to first debootstrap a 64bit into a directory, then collect all 64bit packages and install them but this doesn't work.
To install 64bit of a package they suggest to use package-name:amd64
"Upgrade your 32-bit system closest to the mini system In order to have your 32-bit system as much as compatible (from the configuration files POV) to your mini 64-bit system, upgrade all your packages you have installed in the 64-bit mini root."
but for instance apt-get install zlib1g:amd64 gives
E: Unable to locate package zlib1g
None of the package:arch works at all.
How do I install the amd64 port of a package?
Edit: It seems https://wiki.debian.org/Migrate32To64Bit is outdated and the procedure has changed.