I do not know why I'm asking
I want to know if is possible or not
and that I need pieces for it
and also I to know the I need to upload and download
and that it is better to have them all on one server or distribute, in 1000 alone
A lot of these questions depend on how you're selling your service and usage patterns only you would know.
Yes: It is possible to service 10,000 users with Mikrotik gear.
No: I wouldn't recommend you try to put everything on one device
If you're providing just 256k download and 32k upload then *theoretically* you'd need a maximum of 2500Mbps from your upstream to provide them with access.
Obviously not everyone is online at once or even downloading at once, still looking at 70% online = 1792Mbps
If you did intend to purchase this sort of bandwidth in bulk you should really setup a reliable and fault tolerant network behind it.
If I was building your network, that bandwidth would come from at least 2 upstream providers (say 100Mbps, 100Mbps burtstable to 200Mbps on each, from 2 local upstreams to start with + 1Gbps to the closest IX you can get google+akamai peering from)