Starting point for DE1 Board

You're just creating nets that don't connect anywhere. They're not connected to any pins.

You need to connect them to the VGA ports defined in your top level module. That is, instead of R, connect it to VGA_R, instead of sync_n, connect to VGA_SYNC_N, etc.

If you look at your top level module, you can find in the port declarations all the ports you didn't connect to :

////////////////////////    VGA            ////////////////////////////
output            VGA_HS;                    //    VGA H_SYNC
output            VGA_VS;                    //    VGA V_SYNC
output        VGA_R;                   //    VGA Red
output        VGA_G;                     //    VGA Green
output        VGA_B;                   //    VGA Blue
output            VGA_CLK;                //    VGA Clock
output            VGA_BLANK;                //    VGA Blank
output            VGA_SYNC_N;                //    VGA Sync
output            VGA_SYNC_T;                //    VGA Sync
output            VGA_M1;                    //    VGA M1
output            VGA_M2;                    //    VGA M2