Welcome to the world of marine....thickness of the glass matters most....10 to 12mm will,be on the safer side.
Rocks depends on the land scape you would,prefer to have but live rocks is a must.
Sump tank will be most appropriate and you need to decide whether u prefer biological, mechanical Filteration
No corals means lighting has no restriction. LED would be a good choice.
For fishes...decide which size you would prefer and if possible Quartine the fishes before releasing them into you main tank.
Good cycling of water and ensuring acceptable water parameters is achieved before introducing live stocks...
Is not the display tank that does the job but the sump tank which is hidden below in the dark does the magic of any wonderful marine tank.....