If you'd care to see my list of why I prefer my Rebel over a robot, I'll be happy to share. Others here have to be tired of reading it (or skipping over it!), since I keep writing it over, and over and over!
Short version: get a suction-side vac!
If your builder has installed your suction port correctly, it'll have a safety cover that can be a bit tricky to open, especially by yourself with one hand. Mine has a small slot in it, meant to receive a quarter that can act like a handle. I did that for a while until I discovered it also has a protruding ridge on the hinge that I can use to pry it open with my thumb. I can do that with one hand (the coin is much easier to use with two hands).
(1) See if your suction port has such a cover.
And get one if it doesn't. A suction port is a potentially very dangerous hazard and
must have such a cover.
(2) See if it has a "thumb lever" like mine does, and see if you can work it one-handed with your thumb.

I suppose it will be tempting to try and connect the hose while the pump is running. You really shouldn't. Plus that would make opening the safety cover all that much harder. This is how I connect my vac:
WITH THE PUMP OFF, and the vac hose all up on the deck, I submerge my vac slowly (the manual vac head, in your case), allowing the hose to fill with water as I go. Once the vac head is sitting on the bottom of the deep end, I grab the hose just above the water line, with the other end still on the deck. I then push the hose into the water, allowing the air to escape through the end on the deck. Once I get to the end, I submerge that, and hold it just under the surface with one hand. Now the hose is 100% full of water. Even if the hose is trying to float during this process, it'll still be full of water. I then flip open the suction port safety cover hatch with the other hand, using the thumb lever, and then connect the hose. No air in the line!
Then I start the pump.
Once you get the hang of that MO, I think you'll find it is waaaaaay easier than trying to connect a vac hose to the bottom of your skimmer. Waaaaay, waaaaay easier.
If your safety cover doesn't have the thumb lever (some don't) they are easy to swap out. The one pictured above is only 12 bucks on Amazon.
You just loosen the set screw (you can see it at the bottom of the face on the pic above, blue arrow), and then unscrew the whole thing. Opposite of that to install a new one.