5 of 8 changed the appearance a bit

How to draw Fischer projections for carbon chain having more than two carbons?

How can we draw Fischer projections for one- to five-carbon compounds?

For example, say we have pentane-2,3,4-triol ($\ce{CH3-CHOH-CHOH-CHOH-CH3}$; image below). With wedge and dash structure, the alcohol group is below the plane for $\ce{2^nd}$ and $\ce{4^th}$ carbon but above for the $\ce{3^rd}$ carbon. How can we draw the Fischer projection of this compound?


I read an extract from the chapter about carbohydrates in Solomon's book (10th edition) but only understood partially how to draw Fischer projections as it is given very briefly. Also, a brief introduction is given in chapter 5 but it is for two-carbon compounds only.

I have tried a lot but cannot understand how to construct it or what are the conventions on which they are made. Apparently the web doesn't describe Fischer projections in very detailed way probably because they are generally only used in biochemistry.