Hiya! You say "zip file" which makes it unclear to me ... You're supposed to upload a *.blueprint file - atleast that's what I do, drag and drop from file explorer to that square on the webpage.
Blueprints saves in; C:\*yoursteamfolderhere*\steamapps\common\Valheim\BepInEx\config\PlanBuild\blueprints. Blueprint files are saved with *.png in the same folder.
A10k piece build is like 1MB
