An explanation on how this system work.

First, all stats are rolled in order as listed on the character sheet.

So, if the sheet looks like this:
STR
DEX
CON
INT
WIS
CHR
that is the order in which they are rolled, no expections. If you decide that a stat you rolled is not high enough for the character you want/need then all of the stats for that set are thrown out and you must start at the beginning.

Next, four dice are rolled three times for each stat. You are allowed to only keep sixes that appear on the dice, which you will set aside and not re roll. At the end of the third roll, you read the three highest dice and that determines your stat. Whatever those three number add up to is the stat you are working on, regardless of the total or what is needed in this stat.

Example:
Roll number one produces these four numbers: 2, 4, 5, 6
The six is set aside and the other three dice are rolled
Roll number two produces these three numbers: 1, 2, 3
No sixes so all are rolled again.
The third and final rolls produces these three numbers: 1, 1, 6
At the end of the third roll, the three highest dice are 6, 6, 1 for a total of 13

If you roll four sixes at any time, one of the four sixes will carry over to the next stat unless your roll four on the very last stat.
Example: While rolling for STR, I get four sixes. My STR will be 18 and I will start with one six set aside as I begin rolling my DEX.

Yahtzee is owned by Hasbro and mention of the name of their game is not a challenge to their ownership or trademark.