DIY Driftwood - branches from backyard

Ok so I'm pretty confused as to how the process is supposed to go with making your own driftwood. Also how to tell if the branch is ready to begin soaking and if you absolutely need to dry it out before soaking it.

I have oak trees in my backyard and collected a few branches of all sizes stripped the bark and started soaking them in my empty 55 gallon tank.

Some of the branches still seemed pretty light colored under the bark (especially the larger pieces ). Was i supposed to dry them out or is that how it should look at first? I'm so confused

Ok thank you ... some of them are a bit too large for my oven lol

I don't have plecos but i don't want to coat them with anything. Is there any way of knowing, without breaking the branch apart, if the wood is completely dried out? My boyfriend suggested putting a wire mesh grate over some hot coals and drying the branches out that way ... will that work? And how would i know it's dry enough?
The branch i found is pretty cool looking and would rather not have to break it apart. I would like to make a cave/hideout out of it for my dragon gobies or at least for one of them and hopefully I'll come across another branch if they seem to like it better than the rock caves.

Also, just out of curiosity, why does the branch have to be completely dried out before putting it in the fish tank? Will it mess with the water chemical balance other than the ph?

Here's a picture of the branch ... I have scrubbed it a few times to get all the dirt and loose softer bits of whatever off. Probably needs a few more scrubs though lol

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