missing bootstrap in linux cmake-3.21.4-linux-x86_64.tar.gz -file

Today I downloaded the cmake source-file mentioned in the subject (size 44684259) and wanted to install, but this failed. According to the instructions (on https://vitux.com/how-to-install-cmake-on-ubuntu/ :
"Finally, run the following commands to compile and install CMake:

However, the bootstrap-file is missing, so I cannot install this file. Could the tar-file be corrected and the bootstrap-script be added to cmake? Thanks

The cmake-3.21.4-linux-x86_64.tar.gz is a binary tarball, not the source tarball, so there’s no need to bootstrap it; it is already compiled.

It is indeed. I ran configure, and subsequently make Install, without any problem. Thanks for pointing me to the evident.