First of all, click the Accounts button in the top menu, then Add new account... :
Now you have to set up your account settings.
In Account Name section type ColdStack
In Account Type choose S3 Compatible Storage
In REST Endpoint type s3.coldstack.io
Put in your credentials in Access Key ID and Secret Access Key sections
Setting up ColdStack credentials in S3 Browser
Then click on Advanced S3-compatible storage settings at the bottom of the window. It will open a new window. Select Signature V4 and then click on the Close button:
Setting Signature V4
Turning off multipart downloads
Go to Tools -> Options:
A popup will open. In that windows go to the section "General" and turn off the option "Enable multipart downloads with part size":
Using ColdStack
Now you are ready to use ColdStack! Lets create a bucket:
Type a name for your bucket. Be sure to include only letters, number and dashes: