UE4 Flags

Model of the flag.
The number of tris the flag has controls how fluid the simulation will be. The flag pool and flags mush have sperate materials.

Rigging the flag.
The root is intended for the flag pool, and one more bone is added to be binded to the flags. Export the mesh with its skeleton.

Imported the skeletal mesh.

Enabling the section selection allows for the selection of parts of the mesh based on the material they have.

Moving to the physics asset and selecting the root allows for adding a collision box.

Moving back to the skeletal mesh and right clicking on the flag creating and then applying clothing data to the material.

Under the clothing window select the clothing data created and click activate cloth paint. Here is where you paint the areas the wind will affect, pink means static, white means 100%.
Note: for full wind simulation set the paint value to 1000.

Pressing H while painting simulates the flag. Changing the values in the cloth config controls how the flag will react to the wind when simulating during play.