Batching in DirectX - c++

Question

I have done a framework so far in DirectX 9 and It uses a Single VertexBuffer which draws every texture I load, I have used one Vertex Array which draws every single Texture Quad inside of a Lock and Unlock call. I have heard there is a thing called Batching where I can Lock it once and Unlock when I draw everything. I know I can draw every texture quad in one call to lock and unlock but I have no idea how i can set different textures to each of these. Can Anyone here Guide me ?
vertexBufferRHW->Lock(0, 0, (void**)&VerticesRHW, NULL);
VerticesRHW[0].Color = color;
VerticesRHW[0].X = (float) Position.X;
VerticesRHW[0].Y = (float) Position.Y;
VerticesRHW[0].Z = 0.0f;
VerticesRHW[0].RHW = 1.0f;
VerticesRHW[0].U = 0.0f;
VerticesRHW[0].V = 0.0f;
VerticesRHW[1].Color = color;
VerticesRHW[1].X = (float) (Position.X+TextureFile.Width);
VerticesRHW[1].Y = (float) Position.Y;
VerticesRHW[1].Z = 0.0f;
VerticesRHW[1].RHW = 1.0f;
VerticesRHW[1].U = 1.0f;
VerticesRHW[1].V = 0.0f;
VerticesRHW[2].Color = color;
VerticesRHW[2].X = (float) (Position.X+TextureFile.Width);
VerticesRHW[2].Y = (float) (Position.Y+TextureFile.Height);
VerticesRHW[2].Z = 0.0f;
VerticesRHW[2].RHW = 1.0f;
VerticesRHW[2].U = 1.0f;
VerticesRHW[2].V = 1.0f;
VerticesRHW[3].Color = color;
VerticesRHW[3].X = (float) Position.X ;
VerticesRHW[3].Y = (float) (Position.Y+TextureFile.Height);
VerticesRHW[3].Z = 0.0f;
VerticesRHW[3].RHW = 1.0f;
VerticesRHW[3].U = 0.0f;
VerticesRHW[3].V = 1.0f;
vertexBufferRHW->Unlock();
spriteDevice->SetTexture(0,TextureFile.TextureFile);
spriteDevice->DrawPrimitive(D3DPT_TRIANGLEFAN,0,2);

Answer 1

You can make all your quads a height/width of 1 and then do a for loop like so:
for( ... loop through all the textures )
{
// create a matrix that scales your quad to make it the correct width/height and in the correct location
D3DXMATRIX matrix, scale, translation;
D3DXMatrixScaling( &scale, texture.width, texture.height, 0 );
D3DXMatrixTranslation( &translation, position.x, position.y, 0 );
matrix = scale * translation;
spriteDevice->SetTransform( D3DTS_WORLDMATRIX, &matrix );
spriteDevice->SetTexture(0,texture);
spriteDevice->DrawPrimitive(D3DPT_TRIANGLEFAN,0,2);
}