First, Video no workie. I'll also point out that lighting is your friend when taking pictures or a video.
From what I can see in the image posted it appears that the bottom coolant hose is nearly off the fitting. BTW, I just had to replace this exact hose because the fan shroud had rubbed a hole in the opposite end of this hose at the fitting mounted to the thermostat housing. Note, the cause for that particular rub on my car was the Mountune 3 pass radiator which is thicker than the stock radiator and moved the fan shroud towards the engine. Most Auto Parts stores will stock Hose Clamp Pliers and these can make it very easy to re-adjust the positioning of this hose. Note, this is a "latching" hose clamp and it will lock open when fully opened up. When that happens a small screwdriver can be used to unlatch the clamp. Another solution for this is to NOT open the hose clamp far enough to cause it to lock open. Most hose clamp pliers employ a latch lever and allow you to latch the pliers at several degrees of open.
Next, there is no radiator cap on the top of the radiator in the Fiesta ST. As a result the reservoir fluid level marks are meaningless unless you know for certain that the system has been vacuum filled. Because there is a giant void in the radiator that is level with that hose fitting you are concerned about you simply add fluid to the reservoir after having an overheat caused by low fluid. The only way to fill that cavity in the radiator is by drawing the system down using a vacuum pump. Unfortunately the Auto Parts stores have NOT gotten up to speed in regards to vaccum fillers and do NOT stock them in the stores, you have to order one on line. I would suggest that you take your car to a dealer to insure it's been properly filled with fluid. Yeah it will probably cost you about 100 bucks but this is something that must be done properly.
Or, if you already have an Air Compressor capable of running air tools in your garage you can order a vacuum filler kit. BTW, I have yet to see any vacuum filler that operates off 12 V or a battery pack with a powered vacuum pump so you must have an Air Compressor of at least 3 hp of power. Note the vaccum is generated by a Bernoulli tube using high pressure air and will take the cooling system down to -25 psi gage in about 7 seconds. I'll also note that the overflow vent on the underside of the reservoir must be blocked before you can pull any vacuum, I use a bit of electrical tape about an inch long. One you have pulled a vaccuum you then close the valve for the vacuum generator and open the valve for your fill hose that MUST be submerged in coolant and you'll have the system filled in about 5 seconds.
