#Crochet and #Sewing folks, I need your help.

I'm making a crochet pencil case. I'm planning to line it with some cotton fabric.

There are three separate panels (two in the images) to be sewn together. Should I line the crochet pieces before I sew them together or after?

I will be doing the work by hand as I don't have an easily accessible machine.

My sewing experience is limited to reattaching a button and making one or two wonky pouches, so assume I know next to nothing about it.

@allysseriordan Easiest might be: take a rectangle of fabric, fold in half. Stitch three sides. Flip "inside out" and now you have smooth seams facing into the liner. Press (iron) seams to keep them flat for when you add the crochet bag over.
Zippers are fiddly things. I would try one quick bag without, perhaps a draw string on top from the crochet bag, and get the hang of the mixed media. Second time, make one with a zipper.
@allysseriordan Stitching a D ring into the seam can be good for something to clip keys to.
If double-lined the fabric lining can also turn into a pen holder, change pocket, wallet pocket, brush holder, etc whatever you normally carry and have to hunt to find.
There are commercial handles (leather, chain...) or will you craft them? With fabric or crochet?
Lots to explore!
@reformSchool thanks :) Loads of idea of explore. It's getting me excited to try all the things (eventually).