Im new, and I need to make a grow box.

First of all, read and read and read, there is a ton of info on this forum that addresses your question. The search button is your friend.

As you read you will find that people create grow spaces of all shapes and sizes depending on their needs and circumstances. Think about if you need only one chamber or multiple chambers -- one chamber let's you take one crop from seed to bud all the way through but multiple chambers lets you have different crops going continuously with a veg area and separate flower area. Multiple chambers means multiple lights, multiple fans, etc so will cost more.

Personally I think you need a minimum of 4' height but there are methods of training your grow to stay low that can work in smaller spaces. Higher is better, though you will want a way to adjust the height of your lights, easiest is some hooks screwed into the top and chains to suspend the lights, simple to move them up and down as needed. Keep in mind that your lights will take some of your height and so will your pots, plus you will need some space between your plant tops and the lights, so a 4' box can grow at most a 3' plant, 2.5' more likely.

Think also about what kind of plant you want to grow. Indica grows smaller and gives more of a body stone (couchlock) while Sativa grows tall and gives more of a trippy head-high.

As for horizontal dimensions, keep in mind that if you want 4 plants and are not getting feminzed seeds then you will want to germ and grow 8-10 seeds or more. At the appropriate stage you will see which are males and trash them to end up with your 4 plants. Sounds like you need minimum of 3'x3'.

Some basic rules of thumb: no more than one plant per square foot, minimum 50w of light per square foot. Each plant gets its own pot (I assume you are growing in soil not going hydro).

"Best" lights are HID (high intensity discharge), which include MH good for veg and HPS good for flowering. Many on this forum grow very successfully with only fluoros, read up. Generally the more light the better -- saving money on lights will result in lower yields and maybe sick plants, which wipes out the investment you make in everything else, so spend as much as you can for as much of the best lights you can.

You will need at least two fans, a small one in the box to blow gently on and around the plants (helps them grow stronger stems), and a more powerful one to vent the cabinet. You need to vent the cab both to give the plants fresh air and to remove heat, which can build up in a small enclosed space full of lights. You want air intake towards the bottom of your box and exhaust at the top -- since heat rises this will draw in cooler air and remove warmer air. The exhaust fan can be inside the box or somewhere on the outside in a vent pipe drawing air out. Have at least the same amount if not more of intake as exhaust (in other words, if you have a 6" exhaust pipe but only two 1" intake holes you won't be using that 6" exhaust very effectively because its intake is too restricted). You also want that exhaust fan to be rated at a cfm that is no less than three times your cabinet's volume. For example, if your box is 3x3x4 that's 36 cubic feet so your exhaust fan should be rated no lower than 108 cfm.

Keep in mind that MJ can smell pretty strong when growing, so you may need a carbon scrubber.

Also very important are a pH meter, proper fertilizer, and possibly a moisture meter.

Read and read before you buy or do anything. I built my first cab a while back before I discovered this site and have had to backtrack and re-do some things, not fun. If you fully educate yourself and create a single plan that will work and build that you will save yourself time and money in the long run and will give yourself the best shot at good yields from the first grow.

Good luck.