At the start of the campaign in your homebrew world, give to your players a campaign primer.
Better, you should give to them two primers.
Write there anything your players will need to create a character:
- How to attribute stats
- Races, sub-races, classes and archetypes allowed
- Alignments and backgrounds allowed
Prepare also a section about rules:
- Optional rules you're going to use
- House rules
- How you do handle character's level advancement, and, if you have chosen xp, how they're gained
Write there what your players should know about your world.
Prepare at least the following sections:
- Main Races and Cultures. You can write just a few lines such as "Dwarves are resiliant, stubborn and reserved. They live in isolated clans deep inside the highest mountains".
- Main Political Organizations. Describe most important realms and cities. You still need few lines like "Toleno is a city of merchants on the island of the same name. In its markets you can buy and sell anything. Thanks to a careful system of light cantrips, the city by night is always lit by bright light and it's known as 'The City of the Eternal Day' ".
- Main Churches&Faith. Describe most prominent gods and religions, what are their most important areas of interest, dogmas, and where live most of their followers. Describe for each cult at least a holy symbol and a myth.
- Maps. Add two maps. One that gives a wordly (or continental) general overview and one focused on the local starting area. They shouldn't be much detailed but they should show your players starting knowledge of the setting.
- History. Again, write two chapters. The first one must be brief, featuring general history, also ancient, of the world, and facts that the players known for sure. The second one focused mainly on recent events of the local starting area.
- NPCs. You should provide a short list with a quick description of the main NPCs important both for a worldwide level and for the local starting area.
You can pick some of the following tips to edit your primers:
- Be short (max 10 pages per primer)
- Write short periods, with spaces between them.
- Use bold for keywords
- Add pictures to make easier the reading
- Give to your players both pdf and printed copies
- Update them as much as you can as the campaign goes on
Primers are a very good method to quickly engage your players and to make them "to feel at home" in a new setting.