I have no idea how to play this game, I am stuck on after doing 3 rolls as there is nothing I can do to move on
It gives an explanation at the beginning, you can even click on the ? on the top right to see the instructions. For a simplified version:
Click Roll - Click on the dice you want to keep
The top of the scorecard on the left gives you the options of what you want to do. The top half only counts how many dice you have of that number. Ex: After the first roll, you have 3 dice of 3's, you keep them, Roll the next two times but didn't get any 3's, if you click on the box that says "Threes", your score will go up by how many 3's you have added together - 9. So on and so forth for the rest of the numbers.
The bottom of the scorecard are a little bit more special. Three and four of a kind, should be self explanatory. Full house, if you don't know poker, that means you have 3 dice of one number and 2 dice of another. If you get a full house and you didn't roll 3 times, you can just click on the box corresponding what you want and it'll give you the points.
Small straight, that is 4 dice that are consequential and large straight is all 5 dice. Ex: Small straight could be 1-4, 2-5, or 3-6. Large straight is 1-5 or 2-6.
Chance is a free space, if you got a crappy roll after the 3 rolls or if you don't want to use the dice for another space trying to get a better roll, you can click on that space and it will add the numbers of the dice for that score. Yahtzee is when you have 5 dice of the same number, extremely hard to get.
If by chance you roll trying to get a score but didn't get what you want, you will have to click on something but it will count as 0. Ex: You have your chance and most of the numbers on the top half filled, you are trying to get a 4 of a kind, you got three 2's but you are out of rolls and all you have open is a 5, 4 of a kind and Yahtzee, you will have to click on something but you have no 5's nor do you have 4 of a kind or Yahtzee, to continue, whatever box you click will now count as 0.
Your score relies on the luck of the dice and how strategic you can be filling in the scorecard. That is essentially Yahtzee. Hope this helps.