Here are some things you will NEED!
Tank
Stand
Canopy
Protein Skimmer
Sump
Return Pump
Plumbing Supplies
Powerheads
Live Rock
Sand
Refugium (not a must, but really helps out)
Calcium Reactor/Kalk Reactor/other calcium dosing method)
Chemical Media Reactor (again not a must, but will really make life easier)
Overflow Pipes
Return Pipes
LIGHTING (this category depends on what you want to keep as far as corals go. MH T5 PC LED)
Other random maintenance gear.
If you have any questions on brands or what things are used for just ask!!
~Michael