1) Yes, you can install SDLO 7.0 on the same server as Backup Exec. It will not make any changes to the current BE database as DLO has its own database.
2) There are multiple methods for installing the DLO agent such as push install or placing the DLO agent installer on UNC path etc.
3) Would recommend to have a look @ the DLO Admin Guide, as this product is considerably different from BE. In a gist, you would creating a "Policy" with desired settings and then assigning this policy to the user/computers for backups.