confusion about "Composition" relationship and "Inheritance" concept....?

while I am learning how to implement OOPS concepts (abstraction, inheritance, overloading ...ect) in vb.net , I am reading UML books.

Where does the concepts UML fit in OOP? Like say "Composition" relationship between classess. According to the definition of composition if there is parent-child relationship. Container class and contained class.
say for example "Bank" is a class and "Bank Account" is another class. with out "Bank" class there can't be a "Bank Account" class and there can be many "Bank account" classess for each "Bank class". Is there a specific way we can implement the various relationships of classess in VB.NET? where does the INHERITANCE fit into all the UML concepts? Pls help me out here ..thank you

First, the bank class should be the only object that can be created outside of the assembly. The bank class though can create objects of bank account and such. You use Public, Private, Protected, and Friend.

we can achive the concepts of UML (composition, aggregation etc..) in vb.net by using the Access modifiers?