Questions about a pattern

[Thatch88]

I need help with a classic string bag. 
The pattern says “ch244. Row 1: sl st in 8th chain from the hook”

what exactly does the 8th chain from the hook mean?

[bgs]

Diagram here explains how to count it.

https://www.craftyarncouncil.com/standards/how-to-read-crochet-pattern

[38lasalle]

Literally.....

Find your chain, look at the hook and string of chains...........the first one.........at the hook level......number 1......count seven more back = 8......

[Granny Square]

An easy rule - conventionally, you NEVER count the loop actually ON the hook.  It's not a chain, or any stitch.  

There is always a loop on the hook, that loop will become part of a stitch in your next transaction, but when that happens a new loop will end up on your hook to replace it.    But until that transaction, it's just a loop on the hook and at that point is just part of the yarn coming from your skein, it's not a part of your crochet fabric yet.

So in the OP's example, after chaining 244, to slst in the 8th chain from the hook ("from the hook" means counting back from your hook in the direction of the last chain you made):  Ignore the loop on the hook, skip the the last 7 chains you made, and slip stitch in the chain beyond that, which is the 8th from the hook.