When assets need to be given out to staff members, there are two methods of doing so. One method is issuing assets, where the asset is to be handed over to the staff member indefinitely. The other method is loaning assets, where the loan will be reasonably short term, with predictable start and finish dates. Loans can also have a cost applied to them, which you would charge to the loanee.
If you wish to loan any of your assets, these assets must be marked as Loanable. You can change the Loanable status of an asset from the Details tab of the Asset window.