Help me with this English homework.

Please help me with the following sentences:

1. The training was really useful. It will help us testing the product.

vs

2. The training was really useful. It will help us test the product.

vs

3. The training was really useful. It will help us in testing the product.

I think the preposition “in” used in the third sentence is really redundant. What is the type of the verb when it is used like verb + object + verb?

I mean if you compare it with make clause, make + object + verb/adjective, example, She made me do the murder.

I think the first one would indicate the testing activity is in progress and the attended training will help in improving the process, and compared to second sentence, it indicates the testing activity will start some time later and the attended training will be useful once it begins.

Please advise!