I would suggest using a ready made seed and cutting soil. Garden soil has bacteria and fungus that can spoil your seeds chance of germination indoors.
Jiffy pots are excellent as mentioned by betsuz. They can be planted out in the ground when the weather conditions suit.
When to plant seeds is difficult to say, it depends on your latitude, a good gardening guide should give you an approximate sowing time.
I would suggest planting in a well lit area but not full sun. Too high of a heat can make the seedlings weak. Maintain a temp in the region of 57- 62 degrees F. for the day and not below 55 degrees F. at night.
You should water the pots before sowing small seeds, then sprinkle them thinly over the surface of the pot. If they are very small mix a few seeds with fine sand and sprinkle the mixture evenly on the soil surface. Seeds often come with instructions as to whether to cover them.
Large seeds like, sweet peas, vegetable peas, and beans may be soaked in water over night to allow them to hydrate. plant those on to a pot and bury them one and a half times their size in depth. a quarter inch thick bean could be planted upto thre5/8ths inch deep.
You will need to water lightly but do not water again until the seedlings have appeared.
When the weather begins to warm outside, place the seedlings in a shelterd area where they get good light, and leave them out all day bringing them in overnight. This process is called "hardening off" after several days plants will acclimatize and when there is little chance of a hard frost they can be safely planted out.