Help with Java - Beginner

I have an assignment that asks the following. If someone could give me some guidance it would be much appreciated. I have never programmed so I don't even know where to start. The assignment reads:
Take a class called seriaf.poo.server.config.Server Config (serial.poo.server.config is the package name) whose role reading from a file configuration parameters, which we will use later in the application server . This class must meet the following constraints:
Class must have two constructors:
One with a String argument that represents the configuration file read
One without arguments, which will consider the default configuration file as server.conf.
ServerConfig type objects must read the configuration file and then read the file to expose parameters methods.
Builders ServerConfig class should throw exceptions if problems reading or interpretation of the configuration file:
java.io.IOException if the specified file does not exist or can not read (the exception is thrown by methods that belong to classes of stream type, so it is not necessary than throwing it on).
seriaf.poo.server.exceptions.InvalidFormatException if at least one line of the file does not match expected (this exception does not exist and will be created).
seriaf.poo.server.exceptions.UnknownKeyException if there configured in a proprietary file known (this exception does not exist and will be created).
seriaf.poo.server.exceptions.MissingKeyException if the file is missing one of the expected properties (this exception does not exist and will be created).
Class must be immutable.
The following properties are only valid ones, which must be in the configuration file:
TCP_PORT - is the TCP port on which the server is configured to accept connections and can be read from objects of type int getTcpPort ServerConfig method ()
MAX_CLIENTS - the maximum number of clients per server can serve, and that can be read from objects of type int getMaxClients ServerConfig method ()
Perform a test for this class (which is to read a file and the display of readings) which placed him in class main method Main.
The configuration file is ServerConfig class read a text file, consisting of lines of the following form:
PROPERTY = value
Any line starting with the # character, followed or not by spaces or characters "tab" is considered as comment and not taken into account.
Lines in the file that do not contain any printable character, but spaces and / or tabs are not taken into account.
No account is taken of spaces (or tabs) at the beginning or end of the line.
An example configuration file:
#this is a comment line
******# Another comment line is this, Which shouldnt BE ignored, FOLLOWED by a line with spaces, That shouldnt Also ignored BE
*
MAX_CLIENTS = 100
*******TCP_PORT = 9000

Notes:
The three exceptions were to be defined very simple implementations. It should be defined as some classes that extend the Exception class, and no need contain only the definition of a constructor with a String argument that does is to call the superclass constructor.
The files will be handed over Java implementations of the following classes: ServerConfig, Main, Message, PrivateMessage, InvalidFormatException, UnknownKeyException and MissingKeyException.
The following classes and methods can be useful in homework. Find them in the API documentation:
String.trim
String.charAt
String.contains
String.startsWith
String.equals
String.split
Integer.parseInt
BufferedReader.readLine
Because you can have two different String objects (with different references) but containing the same text, and the operator == compares the references, the right way which compares two strings is by calling equals:
String a = "abc";
String b = new String (a);
if (a == b) {// <- Incorrect assessment will return false
**// ...
}
if (a.equals (b)) {// <- correctly assessing returns true
**// ...
}