i dont understand how do you know were the mines are and how do you make lines and how do you get the flag thingy 
each number indicates how many mines are adjacent to that number the flag is gotten by right clicking you place a flag where a mine is and left click if a mine isn't there you can only know for sure where a mine is by using the number you already have uncovered for instance if a 1 is only touching one covered block that block 100% has a mine on it but if it's touching 3 2 of those blocks don't have a mine on it.