It is possible to upload your own transactions from within the user role or to upload transactions for other users from within the finance role.
More information regarding uploading your own transactions can be found in the following article:
More information regarding uploading of transactions for users by Finance can be found in the following article:
If the transactions are visible within the tool but not allocated to the expenses it could be that they are not yet assigned to the correct payment method. More information regarding allocating transactions to payment methods can be found via following article: