OK Jac. now that we know your grow space is a 4x4 tent and that your using fabric pots with coco (which is a good combo i used this for many years) we can help you out. In a 4x4 area with the size pots your using you could do up to 8 plants comfortably (there will be of course some people who will say thats too many or who will tell you could fit 40 plants in there but for now just trust me and think of 8 as your max), since you are a new grower i would recommend starting with just 2-4, it will be much easier for you to maintain fewer plants in your beginning stages. As Lachrymology mentioned it is important to mix the coco with perlite at a minimum of 30% perlite to 70% coco, i actually prefer a straight 50/50 mix of the two, he is very close but slightly off with the PH though, coco will work best with a PH of 5.5-6.2, i usually set mine at 5.6 when i mix a nute batch as it will raise slightly over a period of time (the period of time will depend on your setup, i use EnF buckets with a 30gal RO res on a chiller so mine usually takes about 2 weeks to fluctuate that much) , which works because it allows the plants access too all the various nutrients it needs as some nutrients are better taken up at differnt ph levels. Bareback also has good advice in that you should get a MH bulb for veg and use the HPS during flower (incase you couldnt figure this out- he meant "HPS" when he said "hose"
) or as i would suggest start looking into LED lighting, it will cost a fair bit in the startup but the energy savings, cooler temps in your tent, and the versatility of setup will all be worth it i promise! One thing you did not mention is the style of grow you intend to do, will you just be having the pots sit on the floor? are you going to use a flood table? I will tell you that even for a beginner flood and drain setups are quite easy to setup and maintain. PM me if you want some advice on an easy DIY flood and drain setup, you could also just search the forums as theres many threads that go into that but i dont mind PMs
Edit: Also i haven't seen you mention anything about your ventilation, have you purchased a carbon filter and fan yet? and what kind of hood came with your light? if your going to stick with MH/HPS instead of LED then you should definitely get a cooltube hood, this will allow for the best heat extraction of your light, or atleast the best heat extraction of a normal light hood, there are better cooled hoods out there but that gets into water cooling and things you dont need to worry about until youve gotten down the basics of growing.