Help w/ making a follow friends GUI?

You need to use GetFriendsOnline, GetPlayerPlaceInstanceAsync, and TeleportToPlaceInstance

This is an example of what you could do

--The whole script has not been tested, change it your likings

function GetFriends(player) --I do not feel like upvaluing it
    return player:GetFriendsOnline(200) --max is 200 
end 

function GetFriendsInGame(friends)
    local new_friends = {} --dont mean it like thatl
    local placeid = game.PlaceId
    local temp 
    for x = 1, #friends do 
        temp = friends[x] 

        if (temp.IsOnline) then 
            if (temp.PlaceId == placeid) then 
                new_friends[#new_friends + 1] = temp 
            end 
        end 
    end 

    return new_friends 
end 


--you could make a gui that selects a friend, and maybe hit follow friendinto game 
--if you do you then do 

function FollowFriend(player, userId) 
    --player == main player, userId == the player to follow 
    --(if this was for the gui, and the player hit the follow button for the player, you would provide the VisitorId from the online friends table)
    local tp = game:GetService("TeleportService")

    local success, emsg, placeId, instanceId = tp:GetPlayerPlaceInstanceAync(userId)

    if (success) then 
        tp:TeleportToPlaceInstance(placeId, instanceId, player)
    else 
        warn(emsg)
    end 
end     

Cite: GetPlayerPlaceInstanceAsync GetFriendsOnline TeleportToPlaceInstance