I can't figure out how to make anchor in an horizontak scroll

Hi, i’m building a website for an agency and i have pages with horizontal scrolling but when i try to make anchor links it doesn’t work. I have seen some topic where people are saying to make an hidden vertical section to make the scroll animation but i can’t figur it out on my webflow project.
Can you help me i need anchor for my navbar and some slide button. Here’s my links project : Webflow - Le Crayon
You need to go on the pages named : Page surligneur, Page média, Page pinceau
Thes are the pages with horizontal scrolling

Samuel Postel