many seeds low space

Hi, I got alot of seeds, but i dont have many space. So i want to ask what to do?
Shall i plant many seed on less space or they will disturbing eachother? Also how many seeds i can put in pot 40x20cm. 2/3?

1

1 seed per pot, unless you have 100+ gallon pots, then 1 and a half

seriously, don't plant all of them at once. you need at least one square foot per plant if you're growing in a sea of green style, and 2 per plant if you're growing in the traditional style. if you decide to scrog, you could fill a 4x4 tent with one plant, if you let it veg long enough.
and its not a good idea to put more than one seed in a pot, the roots will intertwine and compete with each other, it's much better to use a little smaller pot, one per plant
if you aren't worried about plant count, look up "Sea OF Green", or SOG. you flip the plants young , you only get a couple of oz per plant, but they're small, you can fit 30 or 40 in a 4x4 tent, and they grow fast.
you can get a couple of oz, each, off of 40 plants every 3 month or so...
people usually do this with clones, but if you have a buttload of seeds, why not?

1! Top, lst, and defoliate a bit will make it grow horizontally more.