how to connect relay and physical switch to control light
If you want to control a light from 2 points you need the following circuit (the top one):  



Chances are that your current switch is just on/off (SPST or Single Pole Single Throw) instead of the SPDT (Single Pole Double Throw) switch used in the diagram. You really need the SPDT, but you use it just like the other one. The second switch (B) is your relay, which also has to be SPDT.
If you want to switch from 3 or more points you need the center circuit. Switch A and B remain the same, but you need switch C (repeat C for every additional switch). The center and bottom circuit are the same, they just show switch C in both their states.