EDIT Since I read what Mark H suggested (thanks a lot, I found it very useful) I think my question can become clearer structured this way: Using XNA 4.0, I'm trying to draw a cube. Im using this method: GraphicsDevice.DrawUserIndexedPrimitives<VertexPositionColor>( PrimitiveType.LineList, primitiveList, 0, // vertex buffer offset to add to each element of the index buffer 8, // number of vertices in pointList lineListIndices, // the index buffer 0, // first index element to read 7 // number of primitives to draw ); I got the code sample from this page which simply draw a serie of triangles. I want to modify this code in order to draw a cube. I was able to slitghly move the camera so I can have the perception of solidity, I set the vertex array to contain the 8 points defining a cube. But I can't fully understand how many primitives I have to draw (last parameter) for each of PrimitiveType. So, I wasn't able to draw the cube (just some of the edges in a non-defined order). More in detail: to build the vertex index list, the sample used // Initialize an array of indices of type short. lineListIndices = new short[(points * 2) - 2]; // Populate the array with references to indices in the vertex buffer for (int i = 0; i < points - 1; i++) { lineListIndices[i * 2] = (short)(i); lineListIndices[(i * 2) + 1] = (short)(i + 1); } I'm ashamed to say I cannot do the same in the case of a cube. what has to be the size of the lineListIndices? how should I populate it? In which order? And how do these things change when I use a different PrimitiveType? In the code sample there are also another couple of calls which I cannot fully understand, which are: // Initialize the vertex buffer, allocating memory for each vertex. vertexBuffer = new VertexBuffer(graphics.GraphicsDevice, vertexDeclaration, points, BufferUsage.None); // Set the vertex buffer data to the array of vertices. vertexBuffer.SetData<VertexPositionColor>(pointList); and vertexDeclaration = new VertexDeclaration(new VertexElement[] { new VertexElement(0, VertexElementFormat.Vector3, VertexElementUsage.Position, 0), new VertexElement(12, VertexElementFormat.Color, VertexElementUsage.Color, 0) } ); that is, for VertexBuffer and VertexDeclaration I could not find and significant (monkey-like) guide. I reported them too because I think they could be involded in understanding things. I think I also have to understand something related to the order the vertexes are stored in the array. But actually I have no clue of what I should learn to have this function drawing a cube. So, if anybody could point me to the right direction, it wil be appreciated. Hope to have made myself clear this time