I have a question, how would i go about making a single player hub. I already made a map with doors and after the doors is a point_servercommand with a changelevel command. The problem is how do i make the game remember which levels have been completed. I plan it to be 5 doors, 4 unlocked from the start and 1 locked which unlocks after beating all the previous ones.

EDIT:
I also have another problem i want the single player button to load a map but for some reason it does nothing, here's the code for the button:
"BtnPlaySolo"
{
"ControlName" "BaseModHybridButton"
"fieldName" "BtnPlaySolo"
"xpos" "88" [$GAMECONSOLE && ($GAMECONSOLEWIDE && !$ANAMORPHIC)]
"xpos" "63" [$GAMECONSOLE && (!$GAMECONSOLEWIDE || $ANAMORPHIC)]
"xpos" "88" [!$GAMECONSOLE && $WIN32WIDE]
"xpos" "63" [!$GAMECONSOLE && !$WIN32WIDE]
"ypos" "310" [$GAMECONSOLE]
"ypos" "288" [!$GAMECONSOLE]
"wide" "280"
"tall" "20"
"autoResize" "1"
"pinCorner" "0"
"visible" "1"
"enabled" "1"
"tabPosition" "0"
"navDown" "BtnOptions"
"labelText" "Play!"
"style" "MainMenuButton"
"command" "map (the map name)"
"ActivationType" "1"
"FocusDisabledBorderSize" "1"
}

Why don't you use a prop_button that triggers a math_count or the point_servercommand

I know you're tying to help here, but this is a necropost therefore locking. If this is still a problem for OP, they should make another post.