You need to just keep knitting straight. Until it says to change and if it was a good pattern it would say for how many rows to knit straight for.
Look for the key to the symbols on your graph, which will explain the straight line.
cable knitting, tube knitting, four needle knitting, knitting in the round, and a straight knit
You don't need to, circular needles can be used like straight ones--just pretend the cord isn't there ;)
yrn is the abbreviation for 'yarn' - the material you are knitting or crocheting with
You will have to sew it together.
Grameen is the name of a knitting factory in Dhaka, Bangladesh.
k1tbl1
slip
A marker is a ring placed on a knitting needle between two stitches to remind the knitting that something is supposed to happen there.
"Main Color", usually.
You have to think if you're done or not.
In knitting, k2tog is an abbreviation for "Knit Two Stitches Together," or simply "Knit Two Together."