IPFire 2.25 (x86_64) - Core Update 147
Unbound default + Suricata + Guardian
I configured it according to the wiki, and all web traffic passes without adding the proxy address and port 800.
IP address Status
10.0.30.1/24 Proxy on
I still used this video as a help.
Squid does not work on IPFire?
Iam not able to understand what you exactly want 
What do you exactly have configured? For example you said you use Proxy, Suricata and Guardian addon but link a video with Url filter. I can not know if you also use Url filter now or not. I also can not know what do you use exactly as help from this video. Do you also use transparent proxy or not? Also you dont gave information if you firewall forward blocked or not. Sorry please give more precise information. That are to many questions not clear.
All what i can say at the moment. Proxy and Url filter works. Without Proxy iam not able to reach Internet.
Edit:Because it can looks now on a fast view, that you wrote a tutorial and not asking a question anymore, i added your original title.
I sent IPFire version information and enabled services. It has nothing to do with the problem.
This video was my orientation.
URL filter enabled.
Do I need to configure the firewall?
Does the GUI not redirect traffic to port 800?
No.
Now you send enabled services 
Stll missing use transparent yes/no?
The best choice in my opinion is yes, i only allow the clients who have access to the proxy and block all other. Also you have with a forward block not the possibility to reach internet without proxy. So i use both forward block and custom block rules.
What you maybe mean is, you think if you enable Proxy / Url filter the magic happens without doing anything and only proxy is allowed without any further steps?
no
Yes. I know a proxy like that, total redirection to the proxy.
In the video, the magic happens. The web interface itself sets up.
If i remember correct, there was transparent configured in the video. But this only works for http.
i have done the following steps. Example for green.
Where do I find these custom rules?
Custom rules are for your mission not important its only the explanation for
I think its important first, that only proxy connection works and no direct connection without proxy anymore. If this works you can think about if you use rules to allow what clients can use the proxy or if you want config at the proxy config what client have access.
And of course Firewall forward blocked is not a custom rule. You find information here.
Does not work. I don’t use transparent mode.
Ok! Sorted out. Missing set box Enable custom blacklist, on interface web.
I am used to configuring in the terminal. More intuitive. I intend to configure automatic via WPAD dhcp. I appreciate your cooperation.
Note: blacklist (aka blocklist)
I have read your thread and i know that you do not like the term. But that you rename it yourself does not help others when they are looking for the same problem. So I ask you to use terms like they are used by IPFire and not how you like.
Thank you.
As I am a professor and university researcher, I prefer to be didactic in losing content.