If you have a Wearable device synced to your Peak app you will be given the option to log an activity via the Dashboard page. Once it has synced from your device it will display under "New Activities". Go to each new activity and either click "Add training" if you want to record this activity or "Ignore", if you want to discard it.
Note, if you have more than one wearable synced to Peak, you may have the same training session recorded on each wearable, so be sure to select just one of them (choose the one you feel is the most accurate and "Ignore" the other), otherwise you will be doubling up your training load.
It will then ask you if you want to "Link your activity" and "Create a new Training log". Click on this and it will take you to the Training Diary where you can log your training