diff --git a/lua/SpecSwitcher/init.lua b/lua/SpecSwitcher/init.lua
index a7382b4..abecbb7 100644
--- a/lua/SpecSwitcher/init.lua
+++ b/lua/SpecSwitcher/init.lua
@@ -1,27 +1,81 @@
 local M = {}
 
 local Extension_Map = require"SpecSwitcher.ExtensionMap"
+local Path = require"SpecSwitcher.path"
 
-local Config = {
-    test = "hallo"
+local _config = {
+    descend_dir = {},
+    switch_shortcut = "<leader>n"
 }
 
+local mapping = Extension_Map:new()
+
 function open(filename)
     vim.cmd("e " .. filename)
 end
 
-function M.setup(opts)
-    opts = opts or {}
+function M.Switch()
+    local current_dir = vim.api.nvim_buf_get_name(0)
 
-    for k,v in pairs(opts) do
-        Config[k] = v
+    local file = nil
+    local dir = nil
+    local extension = nil
+    
+    local extension_list = mapping:list_exts()
+
+    extension = Path.Get_Ext(current_dir, extension_list)
+
+    if extension == nil then
+        print("No mapping found")
+    else
+        file = Path.Get_File(current_dir)
+        dir = Path.Walk_Up(current_dir)
+
+        print(mapping:print())
+        local mapped_exts = mapping[extension]
+        local walker_func = Path.Generate_Dir_Walk(dir, _config.descend_dir)
+
+        local filename = Path.Get_Filename(file)
+
+        while true do
+            local current_dir = walker_func()
+            if current_dir == nil then
+                break
+            end
+
+            for _, exts in ipairs(mapped_exts) do
+                local current_path = current_dir .. filename .. "." .. exts
+
+                if vim.fn.filereadable(current_path) > 0 then
+                    open(current_path)
+                    return
+                end
+            end
+        end
+        print("No file found")
+    end
+end
+
+function M.setup(opts)
+    local options = opts or {}
+
+    if options.extensions ~= nil then
+        for _, exts in ipairs(options.extensions) do
+            mapping:add(exts[1], exts[2])
+        end
     end
 
-    local mapping = Extension_Map:new()
+    if options.descend_dirs ~= nil then
+        for _, dirs in ipairs(options.descend_dirs) do
+            table.insert(_config.descend_dir, dirs)
+        end
+    end
 
-    mapping:add("c", {"h", "H", "hh", "HH"})
+    if options.switch_shortcut ~= nil then
+        _config.switch_shortcut = options.switch_shortcut
+    end
 
-    mapping:print()
+    vim.keymap.set('n', _config.switch_shortcut, M.Switch)
 end
 
 return M