Welcome to Halven UI, out of the box this is an UI best suited for dps or tanking due to the Grid2 settings and target/player/focus smooth health loss.
But after some customization and resizing of Grid2 i quess it will work just as well for a healer.
To remove the smooth health loss type /stuf, select target/player and focus, press health bar and deselect smooth fade and fade bar loss.
Other then bar 1 in the middle and bar 2 to the right that pops up in combat bar 9 and 10 are active but set to always be hidden, to get them visible simply type /bar, go to bar 9/10, select "visibility" and deselect "always hide".
The borders for these are parented to bar 10 so both must be set to visible, otherwise it will look like crap.
Also, to activate auras on the nameplates simply type /kuinameplates, go to auras and check "show my auras" and then do a /reload ui.

How to install

1. Remove or save you're current WTF and interface at another location.
2. Extract the WTF and interface inside of HalvenUI.rar to you're world of warcraft folder
3. Go in to the WTF folder, enter account and change "ACCNAME, SERVERNAME and CHARNAME" to yours.
4. When inside type /reflux switch Halven.

Note that the UI is built on a 23" 1920x1080 monitor so if you have a different size on you're monitor you probably need to adjust the UI scale.
Also, reflux doesn't seem to work with AzCastBar and Bagnon so after you have loaded the reflux profile type "/acb", press profiles, select Halven and press load.
And the bag is something you will need to configure after you're own taste.

How to set up your important buffs/debuffs in weakauras if you're not a hunter

1. Type /wa in the chat and go in to the "not loaded" auras and select hunter debuffs, after that select "load" and change it to your class and spec.
Do the same thing in hunter debuffs icons.

2. Press the "+" so you can see the groups children.
Now select for example "BA" and go to trigger and change the auras name to the spell you want to track on the target, then go to "load" and select which class and spec it should load in.
Do the same thing in hunter debuffs icons (BA being black arrow in this group).
Ignore the "load spec" part if you have and want to track the debuff in all specs.

3. Do this for all the other children and if you want to change the name of the group/child simply right click the aura and press rename.
If you want more buffs/debuffs simply right click on a child and duplicate it in both the icons and border group.
Then change the name in "trigger" to the buff/debuff you want to track.
Dont forget to change the "load".

Vital addons

Stuf
Kgpanels
Skada
Bartender4
AzCastBar
Masque + Masque vista
BigWigs + !Halvenwigs
Chinchilla
Fonter
Libsharedmedia + Sharedmedia
nibChatTabs
OmniCC
Phanxbuffs
SLDT
TipTac
Reflux
Chatter

Optional/class specific addons

Errorfilter
ColorPickerPlus
eAlign
Weakauras (tracking demo locks demonic fury + buffs/debuffs)
Postal
nibPointDisplay (vital for rogues, feral druids, demo/aff warlocks, shadow priests, monks and paladins)
nibRunes (vital for death knights)
Mapster
Auctionator
Bagnon + Bagbrother
Atlasloot
Grid2
kuiNameplates
TransparentChatBubbles

Since this is an addon compilation all credits goes to the authors!

OBSERVE that at this time there's nothing that tracks balance druids secondary resource, i quess this can be done through weakauras but since i don't have any druid this is something i can't test.
So for now this is something you will need to add yourself.
Also, i haven't managed to figure out how to merge the demonic fury bar with bar1 yet since weakauras don't receive a unique name when created, so i don't know how to parent kgpanels to it.
If someone knows how to do this, feel free to share
I apologize for these things, i will work on it when i have some time to kill and update the UI.
Here's a couple of addons that may do for now, use border fer9 if you want the same look as the rest of the UI.

niBEclipse
BalancePowerTracker

Known bug, blizzards original raidframes has become visible twice when i have been in a raid, do a /reload ui to get them hidden again.