I have 2 solutions for you:

1. Download my video tutorial on this in the following post.
or
2. Use a free plugin/script called MoCon available at the link below.

Regardless of the path you take, there are some issues regarding the .ma Maya8.5+ file format that you NEED to understand before you begin.

As of Maya v8.5, Maya has restructured their export of the .ma fileformat.

Here is a non-comprehensive list of issues/best practices you should make sure you do when in Maya:

1. Make sure you do NOT bake the keys of your default perspective camera.
(That's assuming you animated the default perspective camera which is a very bad habit. Don't do that)
If you DID animate the default perspective camera, create a separate NEW camera, and PARENT it to the perspective camera, then bake keys for the NEW camera.

2. When you create your Locators in Maya, make sure to RENAME them so they start with: "null_"
As long as the names of your locators start with: "null_" then AE will see them as null objects and place them accordingly.
After the underscore you can name them whatever you want. i.e null_simplymaya , etc.
I personally like to name them null_foreground, null_bg etc...

Here is the plugin/scripts combo that was made a while back also that is free and works well called MoCon:
https://3dmation.com/
https://3dmation.com/maya_to_ae.html