You'll need to supply your seedlings with a complete fertilizer to maintain healthy growth. Most seed packets provide little if any information as to specific germination requirements. I am a big fan of Stokes Seeds in Buffalo, NY because their seed packets are written for commercial growers and provide lots of useful details. When you're growing a challenging type of plant such as primroses, the information they provide is invaluable. It provides specific germination requirements, growth habit, time of bloom, and much more for over 500 different kinds of flowers and herbs.
Containers are a personal choice.
The Gardener's Supply catalog offers over a dozen different seed-starting trays. I recommend experimenting with several. This system gives you a variety of different size containers and a clear plastic lid. Over the years I have settled on four different seed-starting systems. Once the seedlings have their second set of true leaves, I separate the individual plants and put them into their own growing cells.