I did a little research on stack exchange, and found this question that was very similar to my own. However, my education is only that of a freshman in highschool, and I was unable to understand a large majority of their work.
Probability of a winning consecutive $k$-subset out of $n$ coin flips
My question is as follows: You have a weighted coin, 30% chance to fall on tails, and 70% to fall on heads. What is the chance across n coin flips that the coin lands upon heads x times in a row.
I ask that the answer to this question be explained as simply as possible, or for help to implement this in google sheets.