rewrote readme, usage and modifications rst

docs/source/usage.rst

@@ -1,3 +1,28 @@
-How to use the environment with your agents
+Using the environment with your agents
 ===========================================
 
+Environment objects, including agents, entities and rules, that are specified in a *yaml*-configfile will be loaded automatically.
+Using ``quickstart_use`` creates a default config-file and another one that lists all possible options of the environment.
+Also, it generates an initial script where an agent is executed in the environment specified by the config-file.
+
+The script initializes the environment, monitoring and recording of the environment, and includes the reinforcement learning loop:
+
+>>>     path = Path('marl_factory_grid/configs/default_config.yaml')
+        factory = Factory(path)
+        factory = EnvMonitor(factory)
+        factory = EnvRecorder(factory)
+        for episode in trange(10):
+            _ = factory.reset()
+            done = False
+            if render:
+                factory.render()
+            action_spaces = factory.action_space
+            agents = []
+            while not done:
+                a = [randint(0, x.n - 1) for x in action_spaces]
+                obs_type, _, reward, done, info = factory.step(a)
+                if render:
+                    factory.render()
+                if done:
+                    print(f'Episode {episode} done...')
+                    break