Every formal version of checkers uses the forced capture rule and we enforce it here. However many people grew up playing without forced captures and hate it. If this describes you I hope you'll try a few of our tactics problems anyway. I think you'll be pleasantly surprised with how much forced captures add to the challenge and beauty of the game.
With captures compulsory spectacular sacrifices and combinations become available. You can compel your opponent's pieces onto weak squares and destroy them. You can force open the back row and get an early king. And on the defensive side you can trade off your opponent's most dangerous pieces.
One detail; if you have multiple capturing paths available you may choose any of them, but you must follow the path to the end.
Kings may move diagonally forward or diagonally backward one square and may capture forward or backward by jumping over an enemy piece and landing in the empty square behind them. Like pieces if another capture is available from the landing square they must continue the capturing path.
There are popular versions of checkers where kings may move as far as they want along the diagonal and may capture by jumping over many empty squares. These versions are fun and I hope to support them some day but in English Checkers kings are slow.
Unlike in some versions of checkers there is no additional compulsion to capture kings or to capture with kings if possible.
In many places of this site and elsewhere you will see little data blocks that look like '11-15' . These are descriptions of moves and in this case say, 'The checker on square 11 moves to square 15'.
'11x18' describes the checker on square 11 capturing the piece on square 15 and landing on square 18.
'11x25' describes the checker on 11 landing on 25 and capturing pieces on 15 and 22.
Most of the time on this site you can click on the description and see what the move looks like. The square numbering system takes a long time to get used to but it's the standard. In the future I'd like to support the chess notation as well because many people are more familiar with it.
For a complete explanation of the rules check the wikipedia page for English Draughts.
If you're playing at home, and I hope you do, consider these ideas to maximize your enjoyment.
Either player may at any time and for any reason resign to end the game with a loss. This is not considered poor sportsmanship and can help avoid the frustration in playing out a hopeless position.
If both players agree, the game can be declared a draw at any time. Start a new one and maybe try a different opening.
Use a chess clock or download an App. If your time runs out you lose! The shorter the time, the sillier it gets. Try anywhere between 1 minute and 45 minutes per player. You can also give the weaker player more time to think to keep things fair.
The proper move order is to crown the enemy piece if appropriate, make your move, remove any captured pieces, then hit the clock. It should all be done with the same hand.