1) how do you do to get a frontline without bumps?

I used glue about 1/2cm for the front. I use 3 layers of superstick, use hairdryer on medium setting for 1 min, inbetween each layer. Then slowly press the piece down on the edges using a comb with small teeth.

2) How do you clean that glue, I mean perfectly clean it?

I use bubble wrap, instead of mirror slide. Then I let it soak in desolvit for about an hour, then use a power shower (i can adjust the spray to be very strong) to get rid of any stubborn glue, when dry, bubble slide again.

3) How to sleep with your unit? Each time I did, hair was looking horrible and the glue and tape lost their strenght and I did use some fabric to hold it in place

Can use a wig cap, or spray some leave in conditioner before you go to sleep. The glue and tape will lose their strength anyway, i like to change every 5-7 days.

4) Sequel of the previous question : How to avoid itching, because no matter what I do, if I sleep with it will itch me.

Use a comb to press with the teeth where it itches, instead of using your fingers, or press with your fingers not scratch

5) What is the difference between knot bleaching and knot sealing? I have a kit bought from debbie but I don't get the difference.

knot bleach = turn the colour of the black dots lighter, but careful, if you lighten too much, the hair becomes weak

knot seal = coats the knots so the hair is harder to break off, be careful, you need very very little, watch video on how to do it

6) If I dye the unit how to fully dye the hair without dying or damaging the lace.

need something to keep wig still, like a foam wig head, hold and turn upside down, then put dye on comb, and comb through...keep away from base material.