To create a new training for a group, click on the Trainings widget on the lefthand navigation panel:

Then, click the green widget highlighted below and follow the instruct:

Once you click Create New Training, you will be directed to the following trainings creation tool where you can select the group which will take this training, the topic, and the date. Once you are done, click Create New Training. You can learn more about how to create training topics in this article.

If you wish to create a new training for multiple groups, follow the instructions in this article on creating training batches.