diff --git a/rexi/cli.py b/rexi/cli.py
index 0c1c641..35d60ae 100644
--- a/rexi/cli.py
+++ b/rexi/cli.py
@@ -8,6 +8,7 @@
 
 app = typer.Typer()
 
+
 def is_stdin_a_tty() -> bool:
     """Wrapper for sys.stdin.isatty.
 
@@ -16,6 +17,7 @@ def is_stdin_a_tty() -> bool:
     """
     return sys.stdin.isatty()
 
+
 # noinspection SpellCheckingInspection
 @app.command("rexi")
 def rexi_cli(
diff --git a/rexi/regex_help.py b/rexi/regex_help.py
new file mode 100644
index 0000000..c2bd320
--- /dev/null
+++ b/rexi/regex_help.py
@@ -0,0 +1,12 @@
+REGEX_HELP = {
+    r"^": "Start of line",
+    r"$": "End of line",
+    r"(a|b)": "a or b",
+    r"[abc]": "Range (a or b or c)",
+    r"[^abc]": "Not (a or b or c)",
+    r"[a-q]": "Lower case letter from a to q",
+    r"[0-7]": "Digit from 0 to 7",
+    r"\\x": "Group/subpattern number x",
+    r".*": "0 or more characters",
+    r".": "Any chrarcter except \\n",
+}
diff --git a/rexi/rexi.py b/rexi/rexi.py
index 7db04c7..6834cc0 100644
--- a/rexi/rexi.py
+++ b/rexi/rexi.py
@@ -5,8 +5,11 @@
 from colorama import Fore
 from textual import on
 from textual.app import App, ComposeResult, ReturnType
-from textual.containers import Horizontal, ScrollableContainer
-from textual.widgets import Header, Input, Select, Static
+from textual.containers import Container, Horizontal, ScrollableContainer
+from textual.screen import ModalScreen
+from textual.widgets import Button, Header, Input, Label, Select, Static
+
+from .regex_help import REGEX_HELP
 
 UNDERLINE = "\033[4m"
 RESET_UNDERLINE = "\033[24m"
@@ -33,6 +36,22 @@ def __repr__(self) -> str:
         return f"Group \"{'|'.join(map(str, self.keys))}\": \"{self.value}\""
 
 
+class Help(ModalScreen[ReturnType]):
+    def compose(self) -> ComposeResult:
+        with Container():
+            yield Label("Help for regex:")
+            with Horizontal():
+                help_keys = "\n".join(REGEX_HELP.keys())
+                help_values = "\n".join(REGEX_HELP.values())
+                yield Static(help_keys, classes="helpKeys")
+                yield Static(help_values, classes="helpValues")
+            yield Button("Close", id="exitHelp", variant="success")
+
+    @on(Button.Pressed, "#exitHelp")
+    def back_to_app(self) -> None:
+        self.app.pop_screen()
+
+
 # noinspection SpellCheckingInspection
 class RexiApp(App[ReturnType]):
     CSS_PATH = "rexi.tcss"
@@ -67,7 +86,7 @@ def compose(self) -> ComposeResult:
                 allow_blank=False,
                 value=self.regex_current_mode,
             )
-
+            yield Button("Help", id="help")
         with ScrollableContainer(id="result"):
             with ScrollableContainer(id="output-container"):
                 with Header():
@@ -78,6 +97,10 @@ def compose(self) -> ComposeResult:
                     yield Static("Groups")
                 yield Static(id="groups")
 
+    def on_button_pressed(self, event: Button.Pressed) -> None:
+        if event.button.id == "help":
+            self.push_screen(Help())
+
     @on(Input.Changed)
     async def on_input_changed(self, message: Input.Changed) -> None:
         self.pattern = message.value
diff --git a/rexi/rexi.tcss b/rexi/rexi.tcss
index cc9364e..dfe05a6 100644
--- a/rexi/rexi.tcss
+++ b/rexi/rexi.tcss
@@ -1,6 +1,5 @@
 Input {
-    dock: top;
-    width: 100%;
+    width: 70%;
 }
 
 #output-container {
@@ -8,10 +7,47 @@ Input {
 }
 
 #select {
-    dock: right;
-    width: 20%;
+    width: 15%;
+}
+
+#help {
+    width: 15%;
 }
 
 #inputs {
     height: 4;
+}
+
+Help {
+    align: center middle;
+}
+
+Help > Container {
+    width: 50%;
+    height: 70%;
+    border: thick $background 80%;
+    background: $surface;
+
+}
+
+Help > Container > Label{
+    margin: 1 1;
+}
+
+Help > Container > Horizontal {
+    overflow-y: auto;
+}
+
+Help > Container > Horizontal > .helpKeys {
+    width: 10%;
+    margin: 0 1
+}
+
+Help > Container > Horizontal > .helpValues {
+    width: 90%;
+}
+
+Help > Container > Button {
+    align: center middle;
+    margin: 2 2;
 }
\ No newline at end of file
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 8729254..004b0da 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -92,10 +92,10 @@ def test_no_stdin_error(monkeypatch: MonkeyPatch) -> None:
     assert "Invalid value" in result.output
 
 
-@pytest.mark.parametrize('input_value', [True, False])
+@pytest.mark.parametrize("input_value", [True, False])
 def test_is_stdin_a_tty(monkeypatch: MonkeyPatch, input_value: bool) -> None:
     isatty_mock = Mock()
     with monkeypatch.context():
         isatty_mock.return_value = input_value
         monkeypatch.setattr("rexi.cli.sys.stdin.isatty", isatty_mock)
-        assert is_stdin_a_tty() == input_value
\ No newline at end of file
+        assert is_stdin_a_tty() == input_value
diff --git a/tests/test_ui.py b/tests/test_ui.py
index 139a0a9..55eb4f9 100644
--- a/tests/test_ui.py
+++ b/tests/test_ui.py
@@ -53,7 +53,8 @@ async def test_switch_modes() -> None:
     async with app.run_test() as pilot:
         assert app.regex_current_mode == "finditer"
         await pilot.click("SelectCurrent")
-        await pilot.click("SelectOverlay", offset=(2, 2))
+        await pilot.press("down")
+        await pilot.press("enter")
         await pilot.wait_for_animation()
         assert app.regex_current_mode == "match"