The object of the game is to get the most points, which you may attain in any of three different ways over two rounds, by placing monasteries on empty places along the roads, or counsellors on the country's emblem.

1/ Number of Monasteries per Country are scored as follows, in each of the two rounds:

The player with the Greatest Number of monasteries scores a point for each monastery in the country.
The player with the 2nd most monasteries scores the number of monasteries owned by the 1st player.
The player with the 3rd most monasteries scores the number of monasteries owned by the 2nd player.. and so on

2/ Number of Counsellors are scored on the second round only:

If you have the most (or are tied for the most) counsellors in each of two countries connected by an alliance marker (denoted by a small square box
with a number inside it.. the value of the number being irrelevant), you score the total number of counsellors for both countries.

3/ Monastery Chains are scored on the second round only:

If monasteries are linked in a chain at least 4 monasteries long, score a point for each monastery on that chain.   
Monasteries are linked by roads only, NOT alliance lines (ie you cannot link a monastery from Aragon to England), and chains may span more than one country.

To the right of the board, you see a section with 5 cards.  
The top 3 cards are yours. 
On your turn you will play between 1 and 3 of your cards, and at the end of your turn you will replenish your hand back up to 3 cards by a combination of one or more cards from the face down pile (that's the stack of cards shown with the number of face down cards left, located below the Ablegen word), and the bottom two face up cards.

To play your cards, first select ALL the cards you wish to play, and then click OK.  
You can tell a card has been selected by the red frame around it.

To replenish your cards, click on the pile of face down cards or the face up cards until you're back to 3 cards.

1/ On your turn, you can only place Monasteries and / or Counsellors in a single country

2/ If the country is empty, you can only place one Monastery.. otherwise you can place up to two Monasteries or  counsellors or combinations thereof, so long as such placements are legal. 
The interface assumes that if you click on a monastery empty slot on the road, you meant to place a monastery there.  Similarly it assumes that if you clicked on the country's emblem, you mean to place a counsellor on that country. 
You cannot take back moves!

3/ The greatest number of monasteries in a country by a single player determines the total number of counsellors the country will hold.  eg if yellow has 2 monasteries, green 2 in Italy, red and blue 1, Italy can at most hold 2
counsellors regardless of who owns them.  You could own counsellors in a country you own no monasteries for.

4/ Of the cards you play, a single card allows you to play a single monastery or counsellor in a country designated by the card. 
A pair of identical cards allows you to play a single monastery or counsellor in any country you wish.  
To play two counsellors, monasteries or combination thereof you need to select either two cards matching the exact country you want to place things in, or a card for that country and a matching pair (that's how you use 3 cards at once).