Hello again, 
Thanks for your messages. just to let you know, i'm doing that for my passion of making candles, just beside my work,  i'm just an amateur trying to do his website, and by myself ; )...
As you suggested, I've tried to put some css code, unfortunaletly, i'm not sure where to put it, and if it is right.
if you look at the page :
https://ibb.co/fVcJkK9d
the fonts are  all differents, and not displaying the "google poiret font" i've selected
so i'm trying to put this in the css right ?
i went to "google font" and got the css code
i've desactivated the font i've tried, i put "nothing" = no selected font at all, in the fields.
put the code in 2 differents places : one in the page CSS, the other in the CUSTOM CSS style...
https://ibb.co/VW1pXtNH
https://ibb.co/zT6QrDxg
apparently this is not the right way... how to do it ?
it doe snot change a thing