Angelica seeds should be sowed as quickly as possible as their germination ability degrades quickly.
Sowing Angelica Seeds.

When planting in the autumn, sow the seeds where you wish to have the plants permanently reside or in a nursery bed. Seeds should be planted half an inch deep to ensure the seeds are covered. Keep the soil loose and open as long as tools can be used among the plants. Once your angelica plants are established enough to shade the ground well, they may be left to care for themselves.
Transplantation.
Our sources disagree a bit here. The older materials provide the following advice: Transplant your angelica seedlings when still small with a space of about 18 inches between each plant. If not already in their permanent location, transplant your angelica plants in the autumn 3 feet apart.
A modern resource explains that with it's long taproot, Angelica can be quite tempermental if transplanted and recommends not covering the seeds.
Angelica Propagation.
Plants may not produce seed until the second growing season. Be vigilant in seed gathering otherwise your garden may become overrun with Angelica seedlings the following spring. Once allowed to produce seeds (typically the second year), most Angelica plants will die. Cutting the flower heads and preventing the formation of seeds will allow the plants to live for several additional years.
Harvest.
Harvest Angelica stems in April or May; leaves in May or June, before flowering; and the roots should be gathered late fall.
Angelica Kitchen Uses
stems and leaf stalks, leaves, seeds, Angelica oil, candied Angelica
The Angelica plant is one in which virtually the entire plant can be used in the kitchen for cooking.
Stems and leaf stalks.
While still succulent can be used as salad greens or roasted or boiled like potatoes. Angelica stems can also be blanched like celery.
Leaves.
Tender Angelica leaves can be boiled and are similar to spinach. They are also used as a garnish for meat and fish.
Seeds.
Angelica seeds are aromatic and bitterish; they are used to flavor beverages, cakes, candies, and comfits.
Angelica Oil.
Used for flavoring and obtained from the seeds and sometimes the roots through distillation. Oil obtained from Angelica root yields about one pound of oil from 200 pounds of root.
Candied Angelica.
Made from fresh roots, tender stems, leaf stalks and the midribs or the leaves.