To create a custom module, you need to create a folder MyModuleName on your folder add-on. On this folder you creae folders/files like this :

MyFolderName

-i18n

-security

--ir.model.access.csv

--security.xml

-__init__.py

-*- encoding: utf-8 -*-
import nameOfMyPyFile

-__openerp__.py

# -*- encoding: utf-8 -*-
{
    "name": "MyModule",
    "version": "1.0",
    "author": "You",
    "website": "",
    "sequence": 0,
    "certificate": "",
    "license": "",
    "depends": [
            "web",
                "base",
    ],
    "category": "Generic Modules",
    "complexity": "easy",
    "description": """

    """,
    "test": [
    ],
    "js": [
    ],
    "css": [
    ],
    "qweb": [
    ],
    "demo_xml": [
    ],
    "images": [
    ],
    "init_xml": [
    ],
    "update_xml": [
        "security/ir.model.access.csv",
        "security/security.xml",
    ],
    "auto_install": False,
    "installable": True,
    "application": False,
}

-nameOfMyPyFile.py

He inherit the base .py and contains your code.