A permanent dye will give you much better results than a semi-permanent dye because it contains ingredients that are capable of lightening your hair. A demi-permanent dye will open the cuticle to allow more color in, but it will not lighten your hair color. A cool tone is also highly recommended as it will reduce the chances of your hair coming out brassy. If you have dark hair and wish to go brown, opt for a light or medium ash blond color. Gather all of your hair, except for the bottom layer (about mid-ear-level and below). Twist it into a loose bun at the top of your head, then secure it with a clip or hair tie. Cover your counter with newspaper or plastic. Drape an old towel or a dyeing cape around your shoulders. Apply some petroleum jelly to the skin along your hairline, back of neck, and ears. Lastly, put on a pair of plastic gloves.  You can also throw on an old t-shirt instead of using a towel or dyeing cape. You may not need to by a new pair of plastic gloves. Many hair dye kits contain them. In most cases, all you have to do is pour the dye into the applicator bottle containing the cream base, then shake the bottle to mix. Some kits also contain extra goodies, such as a shine oil, which you should add in as well. You can also mix your dye in a non-metal bowl using an applicator brush. Start applying the dye to your roots, then blend it down towards the roots using your fingers or an applicator brush. Apply more dye as needed.  You can apply the dye directly to your hair using the applicator tip on the bottle you mixed it in. If you prepared the dye in a bowl, use an applicator brush to apply the dye to your hair instead. Undo the bun on the top of your head and let down another layer of hair. Gather the rest of the hair back up into a bun, and apply more dye to this new layer. Keep going until you reach the top.  Be sure to dye the fine hairs on your sideburns and temples. You want to dye the top of your hair last because it will process the fastest.  If you have very thick hair, then you may need...

TL;DR in Vietnamese:
Chọn màu nhuộm, tốt nhất là màu có tông lạnh. Chia tóc thành nhiều phần. Bảo vệ da, quần áo và bề mặt làm việc. Chuẩn bị thuốc nhuộm tóc theo hướng dẫn. Phết thuốc nhuộm lên tóc. Nhuộm phần tóc còn lại theo từng lớp. Quấn tóc thành một búi và chờ thuốc nhuộm lên màu. Xả sạch thuốc nhuộm bằng nước mát và dùng dầu xả. Làm khô tóc và tạo kiểu tùy thích.