My course is very basic and hasn't done a whole lot of in depth explaining
For the stupidly simple things, you ARE expected to experiment and RTFM.
What does
for(int row=0; row<10; row++)
{
for(int col = 0; col < row; col++)
{
Serial.print('*');
}
Serial.println();
}
do for YOU?
Can you see what you need to adjust to get the right number of rows?
Can you see what YOU need to adjust to get the right number of columns per row?
Can you see that MEANINGFUL names make a lot more sense than i and j?