Understanding the Pattern

Can someone please clarify the following:

When a pattern says inc 1 st at each end of 5th and every following 8th row what does it mean?

Is the 8th row counted from the first or from the 5th?

So do I increase on Row 5, Row 8 and then Row 16 OR Row 5, Row 13 and Row 21?

Gateful for your help.

Because it says “…every following 8th row” it means to increase at each end of rows 5, and then 13, 21 etc.

Thank you for clarifying that for me x