I usually download the three files:
bitcoin-28.0-x86_64-linux-gnu.tar.gz,
SHA256SUMS and
SHA256SUMS.asc and place them in the same folders for easier verification.
I do this by following the verification instructions on the download page:
https://bitcoincore.org/en/download/, below there is a section:
Verify your download and then you can open
MacOS verification instructions to see the instructions for your OS.
Did you import the keys of all the devs who signed the binary? I ask this because I didn't see if you downloaded the gpg keys from the core devs in your answers. Below is the command for this:
gpg --import fanquake.gpg
As DireWolfM14 specified, follow the instructions on the
download page, below the executables there is a help section for verifying signatures.