When someone hovers over the brick for it to say something, how do I add text?

I did the GetMouse Method and didn't find anything else.

You could add a gui to it using the GetMouse method of a Player (in a LocalScript of course), we can access their Mouse and what it is 'hovering over'.

local Player = Game.Players.LocalPlayer
local Mouse = Player:GetMouse()

Mouse.Move:connect(function()
    if Mouse.Target and Mouse.Target == Workspace.SpecialHoverBrick then
        Player.PlayerGui.ScreenGui.SpecialHoverGui.Visible = true
    elseif Mouse.Target and Mouse.Target ~= Workspace.SpecialHoverBrick then
        Player.PlayerGui.ScreenGui.SpecialHoverGui.Visible = false
    end
end)