Vlan

So I’ve been trying to figure this out and i really am struggling and I have rang sophos a few times and well been met with a quick dead tone of the phone :/ 

so we have our main switch which is HP 5400zl series switch and our utm and then from utm to our isp

what I’m trying to is create a guest WiFi on our network, our AP are managed via sophos central 

I have created the ssid and enabled the captive portal and have placed the It in the vlan10

On the utm i have created the interface 10.10.10.1 / 24 as the default gateway and places this in vlan10

on our main switch i created vlan 10 and also enabled IP routing and added 10.10.10.0 /25 10.10.10.1 (not sure if this is the correct way or not)

I have been using another switch (has vlan 10 on it) with an AP and a laptop to test connectivity 

I have also created a DHCP scope so that when a client connects to the guest WiFi it will get an up address out of the scope 

I know how to tag ports etc but I could just do with some extra guidance if anyone could help 

our main network is 10.25.8.0 with the default gateway for our utm 10.25.8.2 (hence) me trying to use a different interface on the utm

do I need to create a static route on the utm ? in order for the communication to work ?

Thanks