Typescript Error

Hello I am new to Ionic2, I have a problem getting a navigation with a new page.
I dont know, which type of error it is. Here is the problem below. I need help –

**Typescript Error**
Cannot find name 'nextPage'.

Ionic Framework: 3.0.1
Ionic App Scripts: 1.3.0
Angular Core: 4.0.0
Angular Compiler CLI: 4.0.0
Node: 7.7.4
OS Platform: Windows 10
Navigator Platform: Win32
User Agent: Mozilla/5.0 (Windows NT 10.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36

Not a lot to go on here, but when you use an identifier defined in file A.ts in file B.ts, you need to put import {foo} from A in B.ts.

Thanks, I did a silly mistake…