I'm using RasberryPI 4b wireless 2gb and install pi-hole in recommended way and using Crosstalk Solutions tutorial.
I'm trying set dns in my xiaomi router and i can't find anything else related to it or in other words I can't find settings to setup dns server and there is nothing else than ddns which give me only 4 options:
-oray.com
-PubYun.com (3322.org)
-Dyndns.com
or No-ip.com
Yes, i'm new with using pi-hole, and trying to use it by wlan.
Searching the Internet, I find various stories for xiaomi indicating either it can't be done, you have to use a smartphone app, or you have to click on specific menu items (maybe that depends on which model).
I found this link that may give you a hint. But like I said, it may be completely different on your hardware, that was just a 5-minute search.
I'm unfamiliar with your router, so I can't provide any specific advice.
Just note that DynDNS is about public DNS servers knowing a name and IP for your router, i.e. it is not related to configuring Pi-hole for your network.
You should look for DNS server options.
There may be two sets of options, one related to your router's upstream DNS servers (commonly, a WAN or Internet setting), and another one related to the DNS servers that your router would tell its clients to use (commonly, a LAN or DHCP kind of setting).
Not all routers expose both options - either one is good to make use of Pi-hole, though the latter would be preferred, in order to attribute DNS requests to individual clients.
You'd have to consult your router's documentation and support channels for further details on its DNS configuration options.
Open browser and type 192.168.31.1 or router.miwifi.com
Click on Settings / Network settings and you will see DNS1. That's where you put your pihole IP address.