How can I hide (Or mask?) a picture when it passes a certain line?

[AARON5C32]

Hello Adobe community,

I recently started toying with AE (Ver: 17.1.4) after some experience with Premiere. I wanted to do something simple yet interesting; and wanted to animate a sort of disc being inserted into a kind of DVD slot. I have provided an image showing what the basics would be. I tried experimenting with masks but I could not figure them out due to me being new to the software. So, how am I able to replicate the effect in the image?

[Mylenium]

Well, you don't need to figure anything out if you only read the online help and then based on that dig for additional tutorials. Just sayin'... Also in your case you also might want to cover the subject of track mattes and possibly also something as trivial as a linear wipe effect to clip away the relevant parts of your disc.

Mylenium

[AARON5C32]

...That's probably a better idea than beelining to the forums for something real simple.