You’ll be prompted to make a backup as soon as you create an account (wallet model)  at OpenLedger DEX.

You need to create this backup file (bin.file) because only using it you will be able to login into your account. 

Only when you agree with all statements you will be able to hit the ‘Download file’ button to get a backup .bin file available for download. 

Download the file and save it in at least two secure places like a USB flash drive and cloud storage.