You will continue to get the map tags even after you have finished collecting the necessary number of items.
For nectar, you may have to raise your Nectar Making skill and manufacture the necessary nectar bottles. For those items that can be collected, your sim will generally be able to use the Map View to find them - just look for a map tag that leads you directly to the item. Your sim will be asked to collect or create a certain number of a particular item: bugs, rocks, gems, metals, and nectar. Some adventures can 'chain' from one to another: accept the first adventure and complete it and your sim will automatically be offered the next part in the adventure. Most of the adventures your sims can go on fall into one or more of the following categories. Each Adventure has certain criteria, and once fulfilled your sim can be rewarded with simoleons, ancient coins, visa points, or relationship gains with a particular sim. EP1: World Adventures allows your sims to perform specific tasks called Adventures.