diff --git a/Cargo.lock b/Cargo.lock
index 9c7e2bc..3ab5f96 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -628,6 +628,7 @@ name = "installer"
 version = "0.1.0"
 dependencies = [
  "system",
+ "thiserror",
 ]
 
 [[package]]
@@ -676,6 +677,7 @@ dependencies = [
  "dialoguer",
  "futures",
  "indicatif",
+ "installer",
  "system",
  "tokio",
 ]
diff --git a/crates/installer/Cargo.toml b/crates/installer/Cargo.toml
index 22af29f..7ec7cd7 100644
--- a/crates/installer/Cargo.toml
+++ b/crates/installer/Cargo.toml
@@ -5,3 +5,4 @@ edition = "2021"
 
 [dependencies]
 system = { path = "../system" }
+thiserror.workspace = true
diff --git a/crates/installer/src/account.rs b/crates/installer/src/account.rs
new file mode 100644
index 0000000..4a93dd5
--- /dev/null
+++ b/crates/installer/src/account.rs
@@ -0,0 +1,97 @@
+// SPDX-FileCopyrightText: Copyright © 2024 Serpent OS Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+/// Identifies an account
+#[derive(Debug, Clone)]
+pub struct Account {
+    /// User ID
+    uid: u16,
+
+    /// Group ID
+    gid: u16,
+
+    /// Account name
+    username: String,
+
+    /// Human username string
+    gecos: Option<String>,
+
+    /// Home directory
+    homedir: String,
+
+    /// Which shell to use
+    shell: String,
+
+    /// New password
+    password: Option<String>,
+
+    /// Builtin user? (root)
+    builtin: bool,
+}
+
+impl Default for Account {
+    fn default() -> Self {
+        Self {
+            uid: 1000,
+            gid: 1000,
+            username: "user".into(),
+            gecos: None,
+            homedir: "/home/user".into(),
+            shell: "/bin/bash".into(),
+            password: None,
+            builtin: false,
+        }
+    }
+}
+
+impl Account {
+    /// Return an account definition for the root account
+    pub fn root() -> Self {
+        Self {
+            uid: 0,
+            gid: 0,
+            username: "root".to_string(),
+            homedir: "/root".to_string(),
+            builtin: true,
+            ..Default::default()
+        }
+    }
+
+    /// New account with the given username
+    pub fn new<S: AsRef<str>>(username: S) -> Self {
+        Self {
+            username: username.as_ref().to_string(),
+            ..Default::default()
+        }
+    }
+
+    /// Update the IDs
+    pub fn with_id(self, uid: u16, gid: u16) -> Self {
+        Self { uid, gid, ..self }
+    }
+
+    /// Update the gecos
+    pub fn with_gecos<S: AsRef<str>>(self, gecos: S) -> Self {
+        Self {
+            gecos: Some(gecos.as_ref().to_string()),
+            ..self
+        }
+    }
+
+    /// Update the shell
+    pub fn with_shell<S: AsRef<str>>(self, shell: S) -> Self {
+        Self {
+            shell: shell.as_ref().to_string(),
+            ..self
+        }
+    }
+
+    /// Update the password
+    pub fn with_password<P: AsRef<str>>(self, p: P) -> Self {
+        Self {
+            password: Some(p.as_ref().to_string()),
+            ..self
+        }
+    }
+}
diff --git a/crates/installer/src/engine.rs b/crates/installer/src/engine.rs
new file mode 100644
index 0000000..9f7c6fc
--- /dev/null
+++ b/crates/installer/src/engine.rs
@@ -0,0 +1,53 @@
+// SPDX-FileCopyrightText: Copyright © 2024 Serpent OS Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+//! Concrete implementation of the isntaller
+
+use system::{
+    disk::{self, Disk},
+    locale::{self, Locale},
+};
+use thiserror::Error;
+
+use crate::Model;
+
+#[derive(Debug, Error)]
+pub enum Error {
+    #[error("disk: {0}")]
+    Disk(#[from] disk::Error),
+
+    #[error("locale: {0}")]
+    Locale(#[from] locale::Error),
+}
+
+/// The installer does some initial probing and is used with a Model
+/// to build an execution routine
+pub struct Installer<'a> {
+    /// Complete locale registry
+    locale_registry: locale::Registry,
+
+    /// Available / loaded locales
+    locales: Vec<Locale<'a>>,
+
+    /// All known/useful disks
+    disks: Vec<Disk>,
+}
+
+impl<'a> Installer<'a> {
+    /// Return a newly initialised installer
+    pub fn new() -> Result<Self, Error> {
+        let locale_registry = locale::Registry::new()?;
+        let disks = Disk::discover()?;
+        Ok(Self {
+            locale_registry,
+            locales: Vec::new(),
+            disks,
+        })
+    }
+
+    /// build the model into a set of install steps
+    pub fn compile_to_steps(&self, _model: &Model) -> Result<(), Error> {
+        todo!("dont know how")
+    }
+}
diff --git a/crates/installer/src/lib.rs b/crates/installer/src/lib.rs
index 8969fcf..6181c2c 100644
--- a/crates/installer/src/lib.rs
+++ b/crates/installer/src/lib.rs
@@ -3,3 +3,13 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //! Lichen installer APIs
+
+mod model;
+
+pub use model::Model;
+
+mod account;
+pub use account::Account;
+
+mod engine;
+pub use engine::Installer;
diff --git a/crates/installer/src/model.rs b/crates/installer/src/model.rs
new file mode 100644
index 0000000..2dca9c9
--- /dev/null
+++ b/crates/installer/src/model.rs
@@ -0,0 +1,14 @@
+// SPDX-FileCopyrightText: Copyright © 2024 Serpent OS Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+use std::collections::BTreeSet;
+
+use crate::Account;
+
+/// Core model for the installation target
+#[derive(Debug, Default)]
+pub struct Model {
+    /// All accounts in the system.
+    pub accounts: BTreeSet<Account>,
+}
diff --git a/lichen_cli/Cargo.toml b/lichen_cli/Cargo.toml
index 7b2d418..7098f79 100644
--- a/lichen_cli/Cargo.toml
+++ b/lichen_cli/Cargo.toml
@@ -10,5 +10,6 @@ dialoguer = { version = "0.11.0", features = ["completion", "fuzzy-matcher", "fu
 indicatif = "0.17.8"
 futures.workspace = true
 tokio.workspace = true
+installer = { path = "../crates/installer" }
 system = { path = "../crates/system" }
 console = "0.15.8"