P2419H, PC has no DisplayPort?

* The P2419H User's Guide page shows us on page 21 that it has the following video in ports = HDMI/DP/VGA

* To access the P2419H four USB downstream ports, the USB 3.0 upstream cable must be connected to the P2419H USB upstream port. The other end connects to the PC USB port

* Once connected like this and both the PC and P2419H are powered on =
PC VGA out port --> VGA to VGA cable --> P2419H VGA in port
* Press the P2419H Input Source button and check VGA

I don't understand this. Both of my laptops have USB and HDMI ports. 

Dell included a DP cable, which I don't have, and an USB 3.0 cable that, based on my understanding, does NOT serve to connect the laptop to the monitor; only to enable the other USB ports. And that is clear based on the fact that the monitor does not work with either laptop when using the USB 3.0 cable.

I do not have any cables. So, do I have to go out and buy an HDMI, VGA, or DP port in other to use this monitor?? Why would Dell include a DP cable, which is less common on laptops, but not an HDMI or even an extra USB to USB cable (assuming that would work once the USB 3.0 cable is plugged in)?

@MiamiCPA  As mentioned above, the USB cable is meant to allow you to use the USB ports on the display with your PC.  The display basically has a USB hub built into it, so if you want to use those ports, you need to create a USB data path between the display and your system.  Video cables do not carry USB data, and USB cables do not carry native video.  USB-C is capable of carrying both over a single cable, but the P2419H doesn't support USB-C even if your PC does.  So if you want video and USB data running between your PC and your display, you need separate cables for each type of traffic.

As far as what cables Dell included, DP is actually quite common on desktops.  It's also more common Dell docks, where there are typically dual DP outputs and only one HDMI output.  Not everyone using displays is connecting them to laptops, after all.  DP is also much more capable, since it can be used for daisy chaining.  And lastly, it is a royalty-free standard, whereas HDMI is run by an organization that requires manufacturers to pay a royalty for every HDMI port or connector they install on products, like HDMI cables or HDMI input/output ports.  But who knows the real answer?  And even in the case of laptops, some laptops only have USB-C ports now.  You don't see Dell including USB or video cables meant to connect this display to those ports.  If Dell included every possible cable or adapter that anyone could possibly need based on every possible combination of PC output and display input, then people might complain that the displays are too expensive or too wasteful in the items they include.  You can never make everyone happy.  But I will note that according to the manual here, the display does come with a USB 3.0 cable.  I'm not sure why you need an "extra" USB cable or why you would expect Dell to provide one.  But whatever the reason, both HDMI cables and USB 3.0 cables are cheap and easy to find.

And just to set some context, your TV likely has multiple HDMI inputs.  How many HDMI cables did it come with?  I'm pretty sure it did not come with one HDMI cable for each input.  It may not have come with any HDMI cables at all.  And your laptop has an HDMI output, but it didn't come with an HDMI cable either.  If every product that had an HDMI connector came with an HDMI cable, you'd end up with twice as many HDMI cables as you actually needed -- and you might still not have any cables of the right length.  Sometimes it's easier to just buy the required cables in the needed lengths rather than paying a premium on every product to have it include a bunch of cables that may or may not be useful to you.