there is a video for k2tog tbl here
in the first column...scroll down they are in alphabetical order
it looks to me like in row 4 you are maybe knitting into the front and the back of the first loop to increase but i could be reading it wrong.
The parenthesis are there because the instruction after them is telling you to do what in in the brackets 2 times. when you have done that you should have 6 stitches on the needle. Then you will increase in the last stitch on your needle and will have a total of 8 stitches.
rows 9 & 10 it is telling you to increase the first stitch and then just purl the rest of the row as normal until the last stitch. when you get to the last stitch you are going to increase again.
all of the increases are what are going to make your shawl into a triangle shape.