Need help with indoor grow set up for auto-flowering seeds

Okay, after some thought I've decided to build my own grow tent/box & start a grow from seeds.

So far I've purchased some wood posts, 8ft tall that I plan on cutting down a foot or two.
I will use these posts to build a frame for the tent.
I need help figuring out what I should use for the walls that will be able to hold the fans and carbon filter needed.
This will be my first indoor grow so any information will be useful ad appreciated.

All I know is that I plan on using 600w HPS lights, know i will need two fans for intake and exhaust. Just not sure of the placement of any.

May you let me know exactly what else I should invest in that wont be too expensive.

I already have some nutrients left over from an outdoor grow (didn't get too far)

I ordered 3 auto flowering seeds:
LSD-25
Girl Scout Cookies
& Dark Purple (don't really know what this is, it came free with my purchase of the other two)

Thank you

Hello there,
Welcome to the forum. You may want to repost this in the Indoor or grow room design forums to elicit more responses. First thing to decide is the area of your grow space in Square feet or metric if you prefer. Once you have your dimensions you can make a decision on the type and power of the system you will use to illuminate your space.

For the walls plywood, MDF,OSB(both can off gas. Google it) even hardboard if you are on a budget your options are many. Flat white paint or line the interior with white plastic or mylar sheet(something you can wipe clean). When making your own enclosure your carpentry must be on point because you want to be sure that your finished product is light tight. If you end up with light leaks get some plastic sheet to seal the light leaks. The white/white sheet is completely light proof the black/white panda sheet is not.

At the top of your box make sure to factor in some "noggins" or cross braces to support your carbon filter/fan and light. Try to hang your exhaust with bungee cord or something with a bit of bounce to reduce vibration. Mounting the fan outside the box on top is another option worth considering and drawing exhaust through the carbon filter inside the box from the top. At the bottom of your box have some light proof intake vents. The intake vents can be passive. Keep in mind your light will generate heat and your plants will transpire moisture so good air exchange is vital.

I live in Europe and wood is a lot more expensive here so people do tend to purchase grow tents because they offer a cost effective solution and cover your basics without testing your carpentry skills. By the time you factor in raw materials and build time/correcting mistakes for a DIY box the tents look more appealing.

I am assuming you are on a budget so do not neglect factoring in your running cost when choosing your light,fans etc. You mentioned growing autos so you can run your light longer and gain more yield at the cost of more electricity. Unless your power is free in which case are you looking for a roommate?

I do not know your experience level with growing. If you are new to it take your time planning and consider all your options.Keep things simple and your initial financial outlay modest. Build your gardening skills first and worry about equipment upgrades later. Without the knowledge of how to maintain a healthy plant no amount of fancy grow gear is going to increase your margins for success. A good quality soil grow is more forgiving than hydroponics. You may be bombarded with suggestions from more experienced members to get this or buy that. Get what you can afford and through your own research confident will suit your needs.

You have already taken the most important steps. You joined a forum full of cannabis enthusiasts and you asked some questions. Next up is to read until you have grasped the basics and then to ask more questions. There will always be somebody who can help you.

I wish you all the best in your new venture.

Cheers,
Will