There may be times when you work on separate Flash files that will ultimately form part of one single animation. Here is a quick and easy way to put these files together into one FLA file for publishing.
Assuming you just want to string the Flash animations together chronologically in one FLA file so that they play back-to-back one after the other you do the following.
> Create a new FLA file which will be your final animation. Make sure it is the correct document properties for your purposes (dimensions and frames per second).
> Go to Insert > Scene for as many FLA files as you are going to place in here. To see how many scenes you have, go to the upper right corner of your stage and click on the button “Edit Scene”. By default you only have one scene, but as you Insert > Scene you will get a list Scene 1, Scene 2 etc….
> Now open the first FLA and select all the layers and right-click on the layer selection and choose Copy Layers.
> Switch to your new FLA file and select the first Layer on Scene 1 and choose Paste Layers.
> Now open the next FLA file, Copy Layers, switch to the new FLA and go to Scene 2. Right-click on the layer and choose Paste Layers.
> Continue until all your independent FLA files have their layers copied and pasted into consecutive Scenes in one new FLA file.
> Now when you Preview your new FLA file, the scenes will play one after another.
> This is also a great way to work because each scene remains it’s own entity for editing purposes.

NOTE: The ability to copy and paste layers is new to Flash Professional CS5.5. If you have an earlier version of Flash you may need to select the entire timeline area and Copy Frames and then select the same number of frames in the new scene and Paste Frames.