Unzip the folder.
Use Ego ERP Archiver 6.1 to properly install this helmet.
Once inside Ego ERP Archiver,
File>Open steamapps/common/F1 2018/asset_groups/animation_package/scenes/incardriver/2018 and select incardriver.erp
(if you don't see this, launch the game and then exit, and try again.
Sometimes when the game is updated the incardriver.erp can disappear.)
Once open, navigate to com_06_helmet_d.tga
Select this and then click Textures>Import
Navigate to Gothic Sauber Folder that you just unzipped
Select Gothic Sauber.dds
If asked to select a mipmaps file, navigate to F1 2018/character_package/drivers/male/unbranded_com_06/textures and select com_06_helmet_d.tga.mipmaps
(Don't worry if you want to play as a female, the helmet is used for both.)
Next navigate to and select com_06_helmet_s.tga
Textures>Import
Select Gothic Sauber S.dds
If again asked to select a mipmaps file, navigate to F1 2018/character_package/drivers/male/unbranded_com_06/textures and select com_06_helmet_s.tga.mipmaps
here's a visual guide, hope this helps.
