Android applications can be installed on your phone by two ways

1. Through the online Google Android Market


Here is the step by step tutorial of installing Android applications on your Android phone through the Android Market:


1. Copy the .apk file into memory card of your Android phone.

2. Go to Android Market and search for SlideMe application installer application and install it.
3. After installing the application, launch the SlideMe application installer. It will show all .apk files present in root directory of your memory card.
4. Select the application you want to install by simply clicking on it. 


2. Though Android SDK


This is the another method for installing .apk files to your android phone.


1. Download the Android SDK.
2. Download USB drivers for Android. 
3. Install the Android SDK on your computer and Android USB drivers.


If you want to install the applications from other sources, goto settings> Application settings> Enable unknown sources. Also goto settings> SD card and phone storage> Disable use for USB storage.You can also enable it later.


4. Now, open the command prompt and type: adb install path/file.apk
where "path" is the full path to APK file and "file" is the name of the apk application. 
5. Open the application on your phone and enjoy.