The "PS4 Tool Downgrade v100 exe" is almost certainly fake and malicious .

for PS4 homebrew or explain how real console exploits actually work?

This kind of software—especially "downgrade tools" for consoles—is almost always for your console.

If you're looking for specific guides or tools, consider the following:

Legitimate jailbreaks rely on running exploits through the PS4's own web browser on specific, compatible system firmware versions. current safe firmware limits