For a User Provisioned Infrastructure (UPI) installation on bare metal, the minimum resources required by each cluster machine are listed in the "Minimum resource requirements for cluster installation" section[1] in the installing guide.
However, they are not listed for a Installer Provisioned Infrastructure (IPI) installations on bere metal.
Therefore, please add to the IPI documentation [2] the same explanation as for UPI, or add that there is no difference between IPI and UPI in terms of minimum resources.

[1] https://docs.openshift.com/container-platform/4.14/installing/installing_bare_metal/installing-bare-metal.html#installation-minimum-resource-requirements_installing-bare-metal
[2] https://docs.openshift.com/container-platform/4.14/installing/installing_bare_metal_ipi/ipi-install-overview.html