Entering Adventures into advancements.scouting.org will be needed for any adventures that are not done as part of a den or pack activity. You don't need to enter the entire adventure at once in souting.org, you can complete individual requirements.
This can be accomplished by doing the following:
Login to https://advancements.scouting.org/ and Make sure you are currently viewing Pack 905 (top Right)
Click on Youth profile on the left
Click View More to the right of your den level (i.e. Lions, Tigers etc.). \
Click on the adventure which you have completed
Fill in the completion date for each requirement completed and a comment.
After that is completed a den leader will need to approve them. If you have completed an entire adventure you should receive the belt loop at the next den meeting.