A common mistake is the angle chosen for the tie-outs/guylines.
I might shoot a video clip just on that...
In the meantime , for a start, you can see the correct angle of the tie-outs for any TT shelter by looking at the tent diagram under " specifications" then "show dimensions" in the product page.
This is the Squall II :


BTW, if you use the side tie-out point (half a way along the long side) use that just to pull the fabric ouit not down, so as to keep the shape of the shelter as you see it above.
Like this :

As a hint ..
See the wrinkles on the rear left side ?
Those indicate that the pole tip on that side is not pulled back as it should.
(keep in mind that often in pictures that is more obvious than in reality, I often see that when I look at my photos but not when looking at the shelter ).
Same for the floor. When you see wrinkles across like that they point to the corner that is not set correctly.