it's extremely easy to do!
So I bought, 909 straight hair extensions from the Hair Shop on Wilshire in Hollywood. (color 1B)
This is what they look like out of the package in one long strand, you can call it a track or weft.
I held the strand up to my head and measured and cut three pieces that went from a little past the ear to the same spot on the other side of my head.
I then glued, with a hot glue gun, the three tracks that are the same length on top of each other so that you have one nice thick piece of hair.
This is just a close up of me glueing the tracks together
don't mind my nasty nails and carpet:)
Then use either fishing wire or jewelry threading and sew the wire to both sides of the track so that it makes a halo for your head. You don't have to really sew it, just use a needle to get the wire through the tracks and then tie like 8 knots so it's nice and tight. Make sure before you knot it, fit it to your head!
This is the product I used
And this is how you put the halo in:)