Custom Assets doesn't appear

Hello,

I bought several assets symbols packs on cartographyassets. I wanted to upload them on Wonderdraft but they don't appear on the Custom Assets neither in the symbols. I have tested every methods told into the forum, respected the example assets and followed Youtube tutorials, this doesn't work. Please, help me, i try since 4 hours. I made screens captures of my problem. Sorry for my bad english, I'm french.

https://preview.redd.it/5xh9vh8q034e1.png?width=772&format=png&auto=webp&s=ca88a8159880b8b51d9380e124cb57245745b64d

https://preview.redd.it/8jiz8236034e1.png?width=1920&format=png&auto=webp&s=04a3e5bf617764954f8d96a4c49a25e795a0df83