What to run
Open CIDR Calculator. It stays in the browser.
How to read the result
Usable count must be at least N. A /24 has 254 usable. A /30 has 2.
If usable count is below N, shorten the prefix and recalculate.
Broadcast and network are not hosts.
What to open next
None. This does not assign addresses or talk to a router.