Add game mode selection guide

README.md

@@ -4,6 +4,8 @@ Imitaion of classic game "Mines" using SDL2 library, with timer and flag.
 
 ## Gameplay
 
+### Basic Gameplay
+
 In the menu, you can determine the map width, height and the number of mines.
 
 Once the game starts, you can use the mouse to click on blocks. The left click will open the block, the right click will set a flag on the block.
@@ -14,6 +16,27 @@ On the right side of the game window, the time spent will be shown.
 
 Sweep all the mines(open all the blocks which can be opened) to win!
 
+### Game Mode
+
+The mode of the game is set according to the number of args:
+1 for local mode, 2 for server mode, 3 for client mode.
+
+#### Local mode
+There must be no arg.
+``` bash
+./mymines
+```
+
+#### LAN mode
+* Server mode
+``` bash
+./mymines <port>
+```
+* Clinet mode
+``` bash
+./mymines <IP> <port>
+```
+
 ## Requirements
 
 * C/C++ compiler(gcc, MSVC, mingw-gcc)
@@ -39,29 +62,3 @@ cd ..
 ### Visual Studio 2019 with CMake
 
 ### Visual Studio Code with CMake
-
-
-## Play
-
-The mode of the game is set according to the number of args.
-In lan mode, you must specify IP address at the second argument.
-
-### Local mode
-There must be no arg.
-``` bash
-./mymines
-```
-
-### LAN mode
-
-#### Server mode
-Two args is needed.
-``` bash
-./mymines <whatever> <whaterver>
-```
-
-#### Clinet mode
-One arg is needed.
-``` bash
-./mymines <IP>
-```