Add namespace restriction to docs

Author: calummoore

collections.mdx

@@ -18,14 +18,22 @@ action.
 
 ## Create a collection
 
-You can create a collection using the client library and calling the `applySchema` method on your polybase instance.
+You can create a collection using the [Explorer](https://explorer.testnet.polybase.xyz) **(recommended)** or by using the client library and calling the `applySchema` method on your polybase instance.
 
 <Info>
-  You can also create a collection via the [Polybase
-  Explorer](https://explorer.testnet.polybase.xyz). You will need to first login 
+  We recommended you use [Polybase
+  Explorer](https://explorer.testnet.polybase.xyz) to create your Collection. You will need to first login 
   and create an account.
 </Info>
 
+
+<Warning>
+  If you use `applySchema` you will need to sign the request [sign the request](https://docs.polybase.xyz/write#signing-requests), and 
+  ensure that your namespace is in the format `pk/0x<hex_encoded_64_byte_public_key>/whatever-namespace-you-want`. Where the 64 byte public key
+  is the public key being used to sign the request.
+</Warning>
+
+
 ```js
 import { Polybase } from "@polybase/client"
 
@@ -59,12 +67,6 @@ const createResponse = await db.applySchema(`
 `, 'your-namespace') // your-namespace is optional if you have defined a default namespace
 ```
 
-<Info>
-  If you want your contract code to be updatable, then you need to ensure that
-  you [sign the request](https://docs.polybase.xyz/write#signing-requests) when
-  creating the contract (the first time you call `.applySchema()`)
-</Info>
-
 <Warning>
   `id` field is unique and mandatory on all collections, and you must assign an `id` using
   `this.id = ...` within the `constructor` function.