Use the following schema to request uploaded files:
http(s)://<hostname>/<bucket_name>/<file_name>
Hostname can be found on the Storage tab -> Storages -> Details.
Example
Your storage is in the Global-1 location. You've created a bucket — mybucket — and uploaded picture.png there:
/mybucket/picture.png
Global-1 location hostname:
s-ed1.cloud.gcore.lu
URL to request the file from the storage:
http://s-ed1.cloud.gcore.lu/mybucket/picture.png
S3 storages support both HTTP and HTTPS protocols.