This needs to be set up and configured by a system admin.
To trigger archiving manually from the ELN, navigate to a dataset and use the Request or disallow archiving button, as shown below.
Please note that the strongbox has a minimum size requirement of 10GB. If a single dataset is below this threshold it will be queued for archiving and it will be archived only when additional datasets in the same Space/Project/Experiment are selected for archiving and the minimum size is reached. All datasets are bundled together and archived together. This implies that if unarchiving is requested for one dataset in a bundle, all other datasets will also be unarchived.
Once the dataset is archived on tapes, the button on the dataset page changes to Unarchive, as shown below. Datasets can be unarchived by using this button.
To unarchive several datasets it is possible to use the Unarchiving Helper tool, under Utilities in the main menu, as shown below. You can search for datasets and select multiple ones to be unarchived.