Update Quickstart.rst

docs/source/Quickstart.rst

@@ -1,7 +1,43 @@
-API
-===
+Quick start
+-----------
+-----------
 
-.. autosummary::
-   :toctree: generated
+Setting the backend
+""""""""""""""""""""
+QiboTN supports two backends cutensornet (using CuQuantum library) and Quimbbackend (using Quimb library) for tensor network based simulations. The backend can be set using the following command line.
 
-   lumache
+For CuQuantum library,
+
+.. testcode::
+   qibo.set_backend(backend="qibotn", platform="cutensornet", runcard=computation_settings)  
+..
+
+and for Quimb library
+
+.. testcode::
+   qibo.set_backend(backend="qibotn", platform="QuimbBackend", runcard=computation_settings) 
+..
+
+Setting the runcard
+""""""""""""""""""""
+Basic structure of runcard is
+
+.. testcode::
+   computation_settings = {"MPI_enabled": False,"MPS_enabled": False,"NCCL_enabled": False,"expectation_enabled": {"pauli_string_pattern": "IXZ",}}
+..
+
+Basic example
+""""""""""""
+.. testcode::
+   # Construct the circuit
+   c = Circuit(2)
+   # Add some gates
+   c.add(gates.H(0))
+   c.add(gates.H(1))
+
+   # Execute the circuit and obtain the final state
+   result = c()
+
+   print(result.state())
+
+..