Fix README

Author: szarnyasg

README.md

@@ -60,11 +60,11 @@ In order to run the container, a `params.ini` file is required. For reference, p
 The container will output its results in the `/opt/ldbc_snb_datagen/social_network/` directory. In order to save the results of the generation, a directory must be mounted in the container from the host:
 
 ```bash
-mkdir out
+mkdir datagen_output
 docker run --rm --mount type=bind,source="$(pwd)/datagen_output/",target="/opt/ldbc_snb_datagen/out" --mount type=bind,source="$(pwd)/params.ini",target="/opt/ldbc_snb_datagen/params.ini" ldbc/datagen
 ```
 
-If the memory limit has to be raised, the `-e HADOOP_CLIENT_OPTS="-Xmx..."` parameter can override the default `-Xmx8G` value.
+If you need to raise the memory limit, use the `-e HADOOP_CLIENT_OPTS="-Xmx..."` parameter to override the default value (`-Xmx8G`).
 
 ### Hadoop cluster