Let's setup a folder with a video to start:

Now open your Flash software and create a new document:

Go to "Modify", "Document" and give the size you want to your Flash document then save already your Flash document in the same folder where you have the video:

You should have this in your folder now:

Back to Flash open the component window by going to "Window", and then click on "Components":

In the components window, open the video section and select the FLVPlayback component:

Click on the FLVPlayback component, hold the mouse button and drag the component onto the stage and then release the mouse:

A FLVPlayback component has been added to your Flash document. Now make sure the component is selected and go to "Window", and then click on component Inspector:

In the component Inspector window double click on the right of "Source":

This brings up a pop up where you can enter a path or browse to a valid video:

Select your video:

Then click ok:

The Flash player is ready now let's resize it very quick. If the "Align" options are not open already go to "Window", and click on "Align" to bring the Align window:

Now with still the component selected click on these buttons (follow the order):

Now you can save and publish your movie, go to "File", and then click on "Publish". Now here is what you have now in your folder:

We just need to upload all these files but the .fla one to a folder on our server and everything should work as expected. Here is what I have now on my server:

So let's take a look:

And here is my video!