Slideshow after flashing of second section

Hello,
When a visitor comes to the website, for a few ms appears the second section and then the Slideshow in the first section.
Why does this happen?

Hi
this is the time needed to load the slideshow and images when your page is rendered
the only way you could "improve" that would be to give some css rules to reserve the needed space in your page
but this is the way it works for all major websites ...

CEd

Thank you for your answer.
Can you help me in order to resolve the problem?

give me the url of your page so that I can check

Have a nice day.
arhontikostoufi.gr/en/

username: demo
password:demodemodemo

what you can do, is to add this custom css code to your page
it will reserve the space for the slideshow (44vw), add a background image which is the same as the 1st slide, and position it in the same way as in the slideshow

hope it helps