No stitch

I’m knitting a pattern in stockinette–let’s say red, red, white, no stitch, red, white. What do I do with the “no stitch” stitch? Will I just knit red, red, white,red, white? If so, why is that block there???

Yes, that’s right: red, red, white, red, white.
No stitch boxes are there to hold a place in the chart, usually because there is a decrease or increase somewhere in that column.