(docs) start working on Terminal instance guide

docs/docs/deep-dive/terminal.md

@@ -4,3 +4,48 @@ sidebar_position: 1
 
 # Terminal Instance
 
+Terminal instance is the main API that allow you to interact with the jQuery Terminal library. To
+access the terminal instance you can use return value from terminal call. Or access it with `this`
+keyword inside methods.
+
+```javascript
+const term = $('body').terminal({
+    echo(...args) {
+        this.echo(args.join(' '));
+    }
+}, {
+    checkArity: false,
+    greetings: false
+});
+
+term.echo('Welcome to my terminal');
+```
+
+In above code you code we disabled the terminal and call echo on terminal instance in `term`
+constant.  We also use `this.echo(...)` to implement `echo` command.
+
+## Common Tasks
+
+Here is a list of most common task you can use with the Terminal. The full list of methos is in
+[Reference Guide](#???).
+
+### Print Text on the Terminal
+
+To print the text you use the `echo` method. The first argument is a value that you want to echo and
+the second are options. More about echo method in [What you can echo?](/docs/deep-dive/echo) Guide.
+
+### Inserting Text Into the Command
+
+### Chaning Command
+
+### Getting The Command
+
+### Clear the Terminal
+
+### Destroy the Terminal
+
+### Pause and Resume the Terminal
+
+### Reading Text from User
+
+### Updating Lines