At the time and date agreed (and presumably at end of the production schedule), the container will be delivered to your premises for packing. Obviously, if you do not expect to make this deadline, you will inform the freight forwarder, who will arrange an alternate date for the container to be delivered, and you should also inform the importer of the possible delay. If you do not intend to use a container, then you would arrange delivery of the goods to particular delivery point (usually that of the freight forwarder) or the freoght forwarder may agreed to collect the goods from your premises. For small, non-containerised cargoes, they will probably consolidate your goods with others into a single container (the freight forwarder will probably do this themselves). If are using palletised cargo, then might deliver to the freight forwarder or to the quay side or have them collect it from you.
The freight forwarder will also prepare the customs bill of entry export document and all appropriate transport documents. Goods moving by seafreight incur obligatory cargo dues payable to Portnet and the freight forwarder will probably arrange for these to be paid (and will bill you accordingly).