I suggest newcomers play as an alliance since on horde side nothing is organised so far. But if you still play want to play as horde no matter want, just join world channel (/join world) so there will be some cooperation at least.
The realm itself is very casual and quite friendly in my opinion. Not even enough people for a full raid on horde side after one week lol but the population is still high and there is a queue on the weekends evenings. Remember that normal classic was around 5k pop and now it’s twice or triple as big as it was. Blizzard increased the pop limit but I have no idea how they will deal with no layers later.