A good way to deal with this is to carve out the shape of your bangs first so you have a nice smooth area around them. Pin them or braid them down so they are out of the way and your sectioning is preserved, and then do your install.
If you’re worried about the actual braided in extensions’ sectioning near your hairline, that is an easy fix, too! You’ll want to do a couple rows of braided in extensions at the nape of your neck first.
You’ll eventually on the 2nd or 3rd row have a row that will go above your ears. Continue this neatly over your ears, up your temples, and just neatly section the areas around your entire hairline (aside from your fringe, of course!).
Because the most visible parts of your hair will have neat sections, you can have a little more leeway with odd sections near the top/sides of your head which is not as noticeable.
Don’t be afraid to use triangle shaped sections or other slightly unusual section shapes if you are at a funny spot on your head. Your head is round so a perfect bricklay pattern isn’t quite possible.
Don’t worry too much.
Also, though our sectioning page is mostly geared toward real dreadlocks, you might take a look at the video there as well as the guidelines on sectioning and apply them to your synthetic install! 🙂
I hope this answer is helpful to you and clear to understand! If you need more tips or if I didn’t answer you quite adequately, feel free to drop us another question or two!