TickGroup - how to understand that?

I want to know more about tick group. But in API this page is missing. Can someone help me to understand this? How many tick groups do we have?
And which tick group we have in blueprints? Can I extend the blueprint tick group?

There are few tick groups. They are used to put specific tick tasks in order, to keep work being done synchronized.

TG_PrePhysics - ticked before physics simulation starts

TG_StartPhysics - special tick group that starts physics simulation

TG_DuringPhysics - ticks that can be run in parallel with our physics simulation work

TG_EndPhysics - special tick group that ends physics simulation

TG_PreCloth - any item that needs physics to be complete before being executed

TG_StartCloth - any item that needs to be updated after rigid body simulation is done, but before cloth is simulation is done

TG_EndCloth - any item that can be run during cloth simulation

TG_PostPhysics - any item that needs rigid body and cloth simulation to be complete before being executed

TG_PostUpdateWork - any item that needs the update work to be done before being ticked

TG_NewlySpawned - Special tick group that is not actually a tick group. After every tick group this is repeatedly re-run until there are no more newly spawned items to run

Thank you very much!
But where Tick from blueprints are placed?
Can I manage these tick groups from blueprints?

In Details if you click on the eye and show Advanced Details you can select the Tick Group between Pre Physics, During Physics, Post Physics or Post Update Work. Pre Physics seems to be the default.

can you activate several tick types for the same actor? or just one? How would you do that?

Found it, FYI: https://docs.unrealengine.com/latest/INT/Programming/UnrealArchitecture/Actors/Ticking/index.html#advancedtickingfunctionality

It look like Anim blueprint are tick even BEFORE the TG_PrePhysics ?
Ok, according to documentation, it is done during the TG_PrePhysics Actor Ticking | Unreal Engine Documentation