Update installation.rst

docs/users/installation.rst

@@ -2,4 +2,38 @@
 Installation
 ==============
 
-TextAttack must use Python >=3.6
+
+### Installation
+
+You should be running Python 3.6+ to use this package. A CUDA-compatible GPU is optional but will greatly improve code speed. After cloning this git repository, run the following commands to install the `textattack` page a `conda` environment:
+
+```
+conda create -n text-attack python=3.7
+conda activate text-attack
+pip install -e .
+```
+
+We use the NLTK package for its list of stopwords and access to the WordNet lexical database. To download them run in Python shell:
+
+```
+import nltk
+nltk.download('stopwords')
+nltk.download('wordnet')
+```
+
+We use spaCy's English model. To download it, after installing spaCy run:
+
+```
+python -m spacy download en
+```
+
+### Cache
+TextAttack provides pretrained models and datasets for user convenience. By default, all this stuff is downloaded to `~/.cache`. You can change this location by editing the `CACHE_DIR` field in `config.json`.
+
+### Common Errors
+
+#### Errors regarding GCC
+If you see an error that GCC is incompatible, make sure your system has an up-to-date version of the GCC compiler.
+
+#### Errors regarding Java
+Using the LanguageTool constraint relies on Java 8 internally (it's not ideal, we know). Please install Java 8 if you're interested in using the LanguageTool grammaticality constraint.