I heard this is possible but I have no idea where to go and who to speak to. How does this work? What chapters can I have my weapons upgraded?

And can someone please explain to me how to scribe scrolls?? I have no idea, lol. :(

In both chapter 2 and 3. Look for a blacksmith in the drow camp, real easy to find. He's also easy to find in Chapter 3, but I won't spoil where. Just think "tavern."

I don't know the second one, sorry.

For scroll scribing:
step 1: get a blank scroll (some stores sell them)
step 2: make sure you have the spell you want to scribe memorized
step 3: go to inventory and find blank scroll
step 4: cast the memorized spell on the scroll by using the radial menu on it

Tadah! Now you should have a new scroll with the spell inscribed on it.

To be honest, this is how it should be, I've never tested it myself.

Meatdog is correct.

Scribing a scroll, however, burns both XP and gold. But it's well worth it so that your wizard or cleric is at full versatility.

You should not neglect wand crafting as well. Purchase bone wands from certain shops, and cast a spell on them.

Scribe high level spells on scrolls and charge low level spells onto wands.