And what exactly is the problem? You are being generic and vague. If there is something specific, you have to explain better, preferably using terminology people actually understand.
Anyone that has spend more than a half hour studying the UI knows how to do this. It's more than basic. If you want to select all 100 layers use the standard shortcut for almost all software for selecting all Ctrl/Cmnd + a.
If you want to nudge the position of a bunch of things you have selected in almost any app use the left, right, up or down keys to move one unit, pixel in AE's case in that direction or hold down the shift key and move 10 at a time.
In most cases, if you have a bunch of layers selected and some are on top of other layers, when you click and drag only the top layers will move. After Effect has a function that you can find in the timeline called Parenting. This allows you to tie layers to a master layer. If you don't know how to find the parenting option or how to use it type Parenting in the search help field at the top right corner of AE and read up. It is easy and a useful tool that everyone using AE should know how to use.
If all you want to do is move the 100 layers around and change their position you can always nest your comp or select the layers you want to group and pre-compose. Again, if you don't know what I'm talking about please use the search help field and do some studying.
For a bunch of how to get started lessons go to the After Effects product page and check out the Learning resources. I'ts highly unlikely that you will be able to get very far using AE without doing some homework.
If, on the other hand, you are an experienced user then we need clarification on your workflow and your problem. It's hard to know what you really need without some details.
Sorry for this issue. Did you ever find a solution? Please let us know if our experts’ advice helped you or if you still need help.