I have set a bleed area that may need changing - how?

Question

Hi. Hope this is not too confusing - My book will finish at 210x257mm.
Printer stipulated 1 page - 216x263mm including 3mm bleeding four sides. 
                            2 pages together, 426x263mm including bleeding 
New at this, I have a red, black and pink line. Is the Pink line the cut off line. (not sure what the red line is)
I have extended my bleed photos to the black line - the part from there to the pink line will be the cutoff ?
From the outside blackline to inside black line the measurement is 216mm. Top black to bottom black line 263mm.
"2 pages together , 426 x263mm including bleeding" - mine over the 2 pages outside black line to outside black line at present is 432mm  x 263mm - I assume that maybe 2 x 3mm bleed in centre? (i.e. pink to pink line = 6mm)
Bit confused here because Printer says 3mm bleeding four sides which includes the centre for 1 page which I have set up
If I need to change something in the Layout how do I do it part way through a Document?
I hope this is not too confusing but would really appreciate some A-Z help before I go any further.

Answer 1

In document setup you should have facing pages checked, and the page dimension should be 210 mm wide and 257 mm high. In the bleed setup fields enter 3mm for all (but see InDesignSecrets » Blog Archive » Breaking Pages Apart to Bleed Off a Spine) if you have any artwork that dies into the spine (crossovers will be fine as-is). The bleed at the spine on a facing pages spread (unless it is split apart) is the edge of the opposite page.
This should give you a red line around the outside tha is the bleed boundary, a black line that is the page boundary, and a magenta (or pinkish) line inside the page that is the margins you've set, which you didn't specify so I can't tell you what to enter.