how to build this vidio with after effect

Everything that you see moving is a separate layer. There is no one technique. The only common element in all of those shots is that they were all made up of multiple layers that were moving. If I were to recreate that video almost every shot would be a separate composition and the final editing would be done in Premiere Pro. I would not create any motion graphics sequences that were longer than a sentence or phrase of voice over.

Everything from position and scale animation to shape layer and text animation are used to create the project.

If you are new to AE you should expect to spend about 20 hours getting familiar with the UI, techniques, and workflows required to do a project like this. It's going to take some time and some practice to get the timing down and make the moves look good. I suggest you start here: Basic AE

Let us know if you run into any problems you cannot figure out on your own. Unfortunately, there is no single tutorial I can point you to that will explain everything you need to do to recreate that video. I suggest you pick out one shot and try and break that down into its component parts.

About what template is that probably no one will be able to tell you. Even if that is some kind of template - there so many of them and most of us does not use paid templates to often that it wil be hard to find exact one. There is also possibility that it is not a tempate at all - and I guess that is the case here -  but original work.
As how it was made - a lot is going on in this composition to give you step by step guide to achieve it but all of this is not some kind of special magic and don't need any special skills - this animation was made with basic knowledge of AE and basic tools. Some transitions, movement, rotation, opacity etc. So first - if you are new to AE start here:

After Effects tutorials | Learn how to use After Effects CC

or

After Effects Basic Training

or many, many more