@b2kzone I think it is difficult to explain vlan clearly in a few words. I think this article is very valuable, you can take a look. Maybe it can answer your question.

http://www.practicalnetworking.net/stand-alone/vlans/

@Yannie hello, I know who vlan works and the theoretical things, where I'm confused is on the part of the  TP-LINK switch mode how they use the "switchport mode general" instead of using trunk or access

Let me say in this way, the part of how vlan works I know from cisco, what is for me unclear is the particular thing of the tp-link switch and this is about "general mode" as an exmaple. Let assume I need a internet connection for a user on the cisco switch I set the port in access mode and set some security features and that's it, after this I can connect to internet and the same for trunk set the mode trunk and some security features and that's it, also here I have the trunk port to transport multiple vlans.

When come to the idea or the way how tp-link implement the idea of a access and trunk port is different and form few tests and a lot of research with a small amount of info I don't understand why I need to use general mode to can give internet connection for a user, also here I will give you an example

At the first time I configured the tp-link switch port for a desktop as

"switchport mode access

 switchport access vlan x

"

with this confing and I the Connection didn't work after a research I read to use general mode but without an explanation so I tried with this config

"switchport mode general
  switchport general allowed vlan x untagged

switchport pvid x

or

switchport mode general
  switchport general allowed vlan x tagged
  switchport pvid x

"

this the part when I don't understand why to use and for what is used generel instead of access or trunk