By A Web Design
To upload and insert a video(s) to a post(s) in WordPress 3.X.X login to WordPress as administrator, by simply entering the url_of_your_website/wp-admin in your Browser. Enter the appropriate username and password {which was provided while installing Wordpress} and then click on Log In as shown in Diagram 1.

Diagram 1
After logging in as WordPress Admin, a Dashboard page opens as shown in Diagram 2.
The WordPress Admin Dashboard provides access to different WordPress functions and features.

Diagram 2
In the left menu, locate the link Posts. Click Posts. From the drop down menu that appears click on Posts as shown in Diagram 3.

Diagram 3
Click the Title of the post as shown in Diagram 4 or click Edit to open the post in its editable mode.

Diagram 4
Once on the post, insert the cursor where you want place the video as shown in Diagram 5.

Diagram 5
Click the upload media button as shown in Diagram 6.

Diagram 6
A dialog box Add Video is displayed. Here, you can add media files from your computer, or from a URL through the WordPress Media Library.
In this tutorial, we will upload a video from our computer. Click Select Files as shown in Diagram 7.

Diagram 7
After clicking Select Files, a file navigator window opens. Navigate to the appropriate folder where the video to be uploaded is located, select and open the file as shown in Diagram 8.

Diagram 8
WordPress will process the video and upload it to media library as shown below:
url_of_ur_website/wp-content/uploads/{year}/{numerical_named_folder}/{all_videos}
A dialog box is displayed with image details as shown in Diagram 9.
Enter the following details as required.
Title: WordPress will put the video name in this field. It’s very useful to insert keywords of your post in this title.
Caption: If you want to wrap the video with the text, leave it empty. The caption should be as small as possible.
Description: It is optional to type in, but in case your video won’t show up, this description will show.
Link URL: This is the path to the video. By default it takes absolute path to image. You can set relative path to video(s).
Once you’re done, click Insert into Post as shown in Diagram 9.

Diagram 9
In HTML view, the codespec to insert a video is displayed where the cursor was set initially, as shown in Diagram 10.

Diagram 10
On the right hand side publish box, click Update to save the changes made on the post as shown in Diagram 11.

Diagram 11
In the front end of website, the link to video has been successfully inserted on the post at the cursor position as shown in Diagram 12.

Diagram 12
Click the link of video, it will prompt you to open the file in any player as shown in Diagram 13.

Diagram 13
The video will be successfully played in any standard video player.