Thank you Liam for your kind help.
I bought a domain name on godaddy,
then I put the 3 DNS ip BCatalyst at the rights places on godaddy,
then I put the name domain on the BCatalyst page of my website.
Actually when I clic on the website to see if it is correct (on my BCatalyst website page)
Safari says he can't find the page.
I am on creative cloud so I know I have the right to be hosted for 5 basic websites...
So what is this new problem ?
I am asking me....