SOLVED very new... Biginteger problems

Hello

I am very new to Java (this is my first java programming) and am puzzeling how to work with Big integers and i am not able to work it out

My problems reduced to simple statements are the following

Declaration

I need to declare a new BigInteger with a value of 1

Multiply a named biginteger by 3

Add one Biginteger to an other (someting like a = a+b but then for Big Integers)

That is all for the moment. (Can it be more simple?)

But even this is above my grasp of Java

I just don't seem to grasp object oriented programming

Can somebody help me work this out?