A bit of VLAN help needed

[dubsdj]

I'm trying to understand what I should do first to get my VLAN up and running.

Scenario

Multiple Netgear managed switches through out the building (Some stacked).

Multiple Wirless AP's connected to the network

Domain

Task

I want to create a VLAN and plug one of my AP's to it.

Problem

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What VLAN should I create?

How would the DHCP Situation work? Would the VLAN cut that port off the main network?

How would a user gain access to the wireless network if the gateway is on the main network subnet?

I'm trying to achieve a secure virtual network that wirless laptops connect to and don't have the ability to ping or connect to any of our domain servers.

but the Internet gateway is on the main subnet and I don't want to mess that up.

Do I need to create a PORT vlan and do some kind of route?

An example would be great if anyone knows of a similar situation

thanks