If you want to field a Dark Angel Deathwing army you will want to create a Dark Angel Deathwing Redemption Force. However if you want to field a force of Deathwing in addition to a regular Dark Angel detachment then you can field a Deathwing Strike Force. You can find the Deathwing Strike Force on page 158 of the 2015 Dark Angel Codex.
Deathwing Strike Force Organization Chart
Space Marine Command Squad
The Dark Angel Deathwing Strike Force has 1 to 3 HQ units and 2 to 12 Elite units. Each unit needs to be either to have the Deathwing special rule or be in a dedicated transport. There is no mention that troops need to have Terminator Armour. This means that the options are open to the Veteran Squads and Command Squads too as long as you stuff them in a Rhino, Razerback, Drop Pod, or Land Raider. Dreadnoughts and Venerable Dreadnoughts need to be in Drop Pods too.
Why field a Deathwing Redemption Force?
The main reason to field a Deathwing Redemption Force is to get a load more Elite units, and specially Deathwing Terminators. Also if you are able to field a Terminator Redemption Force then you get a couple of extra special rules too. The first is that if you team this detachment with a Ravenwing detachment then you can choose when your deep-striking units come in ( from round two onwards). The second special rules is that Deep Strike troops can run and shoot ( or shoot and then run) when they arrive on the table.
The rules say that all units must be held in Deep Strike reserve. However Elite units like Command Squads and Veteran Squads do not get Deep Strike, so as a house rule we say that all units that can Deep Strike, must.