You will see a new layer added.  Motion guides allow you to direct a path you want an image to take. In the new layer, make sure there is a keyframe at the same frame the tween begins.  You may also find it helpful to either lock the layer with the image or move it off to the side before proceeding.   Making sure you are working with the motion guide layer, you will place a "snap" event with your tools (read step 2 below).  In the second layer for motion guide, do the following:

1. Click on the pencil icon on the left, then draw a path you want the image in your motion tween to make.

2. Click on the magnet icon located below the pencil as well as along the toolbar at top. This is what does the snapping action so that the image in the first layer will lock on one end of the path in one of the keyframes and then the same with the other keyframe.

3.  Click on the image and while holding the mouse down you will see a circle get bigger when it touches either end of the path you made.  This means it has snapped on to that end.  If you don't see it at first, keep trying, it is tricky.

After doing both keyframes, you can see if it worked.  Click here to view. If you want the .fla, contact me.

Masking allows you to take a template, or cutout (like a cookie cutter) shape and put images over it.  Using a motion tween, you will see more of what this effect really does.

You may want to now see the effect before doing the steps.  Click here to view it.  If you want the .fla for this, contact me.

The animation is made with 2 graphic symbols (circle, each half is a different color, and the other symbol consists of just the name).  In addition, I have included a motion tween (with rotating effect).  The easiest mixup is knowing which layer has which symbol in it.  The change you want to appear goes in the lower layer, and the symbol that stays in place (outlining the area for the mask effect) goes in the upper layer.

1. Add a layer, making sure there are 2.  

2. Put the name graphic symbol in first layer, and bring in the circle symbol in the lower one.

4. At frame 15, select both layers, and then click insert; frame.

5. Then insert a keyframe only for the lower layer at frame 15.  You should now see a circle with the name, and if intersecting, the circle will be behind the name.

6. Make a motion tween for the lower layer by going back to frame 1 and make a motion tween.  In this one I also selected clockwise under "rotate". You have to select the number of  times you want the image to rotate (2 is selected here).  Place the circle in the first keyframe on one side of the name, and on the other side of the name at the other keyframe of the tween.  Test it to make sure you have a circle moving behind the name.

7. Now select the Mask effect.  Right click on the top layer, and then select mask.  The name will disappear in whole or partly depending on where there circle is at in the frame.  Test the movie and you will now see the mask effect.

To add sound, you must first import it, then in a new layer go to modify; frame; select the "sound" tab.  Then under "sound" select the sound file.  On the right you can modify how the sound is to be played as well.

Buttons can be used with sound as well.  After making a button symbol, go to the keyframe you want the sound to occur, and follow the same steps.  Then anywhere that button is put in the canvas area, you will get that effect.  If you want different sounds though for each button, you will have to make multiple buttons.

Midi files can be added onto a page as background sound, after they are published.   Keep in mind though sound files are big, so the smaller in size they are the quicker the whole flash file will be to download.