Hello, does Anyone knows how hard is to install this square cover? do I need to remove the whole front bumper to install it ? I couldn't find proper instructions online.

 

I just looked at mine and it should be a piece of cake and take around 10 seconds max.
The cover has a little plastic tether about 2 cm long on the inside of the bottom left corner and it is integral to the cover (ie moulded into it).
The end of the tether has a triangular shaped "hook" that goes through a slot in the bottom left corner (looking at the bumper) of the opening, then once inserted through that slot the only way to get it out again (without breaking it!) would be to wiggle and manipulate the "hook" out of the slot.
I can see that slot in your pic.
I didn't try getting mine out as I didn't want to accidentally break the flimsy looking tether, I just wiggled it around a little to get a good look at it and see how it works.
The part you want is part # T2R2870, part # 10 on this page: https://parts.jaguarpalmbeach.com/a/...S/4760010.html
Edit - forgot to add, that little tether is not what holds the cover in place, it's only there to stop the cover falling off completely or getting lost. The cover is held on by two simple clips on one side and a tab on the other side, gently pushed on from the outside, so you don't really need the tether at all to fit the cover.

 

I had to replace mine because the PO had installed a license plate bracket in its place. Nice idea, until you need to tow the car. Took a grand total of 2 minutes to install the part mentioned above.

If anyone would like the bracket I took off just let me know - free to a good home.