First of all, you need to find a hosting provider. Following this link - boonex.com/hosting you will find a list of recommended hosting companies. Their servers match all Dolphin technical requirements and their support teams know Dolphin and are able to help ASAP if there any technical issues.
Second, once your server is ready, you can download download Dolphin
Third, install Dolphin on your web server following the instructions or using the auto-installer (Softaculous) offered by all hosting companies listed on boonex.com
Once your Dolphin package is installed, you can begin to modify and customize it according to your needs.