Add clarifications to bots guide.

docs/bots-guide.md

@@ -87,12 +87,14 @@ You need:
       out the form and click on *Create bot*.
     * A new bot user should appear in the *Your bots* panel.
 
-2. Download the bot's `.zuliprc` configuration file to your computer.
+2. Download the bot's `zuliprc` configuration file to your computer.
 
     * In the *Your bots* panel, click on the green icon to download
-      its configuration file *.zuliprc* (the structure of this file is
+      its configuration file *zuliprc* (the structure of this file is
       explained [here](#configuration-file).
-    * Copy the file to a destination of your choice, e.g. to `~/.zuliprc` or `~/zuliprc-test`.
+    * Copy the file to a destination of your choice, e.g. to `~/.zuliprc`
+      or `~/zuliprc-test`. Note that the destination should be accessible
+      from your Zulip dev environment (e.g. Vagrant or Digital Ocean).
 
 3. Subscribe the bot to the streams that the bot needs to interact with.
 
@@ -269,6 +271,15 @@ None.
     * Ensure that you bot script is located in zulip/contrib_bots/bots/<my-bot>/
     * Are you using your own Zulip development server? Ensure that you run your bot outside
       the Vagrant environment.
+    * Some bots require Python 3. Try switching to a Python 3 environment before running
+      your bot:
+      ```
+      source /srv/zulip-py3-venv/bin/activate
+      ```
+      Note that you can switch back to a Python 2 environment as follows:
+      ```
+      source /srv/zulip-venv/bin/activate
+      ```
 
 * My bot works only on some streams.
     * Subscribe your bot to other streams, as described [here](#how-to-run-a-bot).