[NOOB QUESTION] Transform EFFECT understanding

First Point, the Transform Effect moves a layer exactly like the Layer/Transform controls do. The difference is that you cannot see the motion path in the Comp panel or use the Pan Behind/Anchor Point tool. The layer will move if you adjust the Anchor Point values using the Layer/Transform/Anchor Point values in the timeline. If you use the Pan Behind tool, the layer will not move, but the position values will change.

Second Point: The anchor point for Text and Shape layers is always at 0, 0 by default. Footage layers (Solids, images, videos) have the Anchor Point at the center of the layer. Anchor Point does not have anything at all to do with Composition frame size. You move the Anchor Point to change the center point for rotation and for scale. The default Position property for a layer is at comp center or if written as an array in an expression [thisComp.width/2, thisComp.height/2]

The Position property of the Transform effect is also always at the center of a layer by default, as is the Anchor Point, but if you apply the Transform effect to a Shape or Text layer, the Anchor Point and Position Property will always be at comp center instead of Shape Layer or Text Layer center.

It takes a little getting used to. The Transform effect is not as useful as just setting keyframes for the Layer/Transform properties, but it can be useful for adding some additional movement to a layer that is already moving. 

I hope this gets you started. I suggest you spend a half hour or so in the Learn Workspace to familiarize yourself with the UI. You should also spend some time with the User Guide. Trying to learn AE by poking through the thousands of YouTube recipes prepared by enthusiasts or just poling around in the UI is almost always a waste of time.

When you have specific questions about projects and workflows, please start new threads, drag screenshots to the reply field on the forum that shows the entire UI and the modified properties of problem layers by pressing the 'u' key twice (don't use the Drag & drop here button because we have to download them to see them). After Effects has a very complex UI, workflows can become easily convoluted, and it takes a long time to figure out how to create complex animations efficiently. 

Here is one more trap that new users fall into. After Effects is not a video editing application, it is designed to create animations, motion graphics, visual effects, and composites that you cannot create in an NLE. I've been using AE since it was first introduced, and most of my comps are less than seven seconds long, and I do all my final editing and sound mixing in an NLE like Premiere Pro.