Update modular CRM tutorial to reflect single-layer application structure

docs/en/tutorials/modular-crm/part-01.md

@@ -3,6 +3,10 @@
 ````json
 //[doc-nav]
 {
+  "Previous": {
+    "Name": "Overview",
+    "Path": "tutorials/modular-crm/index"
+  },
   "Next": {
     "Name": "Creating the initial Products module",
     "Path": "tutorials/modular-crm/part-02"
@@ -10,7 +14,7 @@
 }
 ````
 
-Follow the *[Get Started](../../get-started/layered-web-application.md)* guide to create a new layered web application with the following configuration:
+Follow the *[Get Started](../../get-started/single-layer-web-application.md)* guide to create a single layer web application with the following configuration:
 
 * **Solution name**: `ModularCrm`
 * **UI Framework**: ASP.NET Core MVC / Razor Pages
@@ -18,7 +22,7 @@ Follow the *[Get Started](../../get-started/layered-web-application.md)* guide t
 
 You can select the other options based on your preference.
 
-> **Please complete the [Get Stared](../../get-started/layered-web-application.md) guide and run the web application before going further.**
+> **Please complete the [Get Stared](../../get-started/single-layer-web-application.md) guide and run the web application before going further.**
 
 The initial solution structure should be like the following in ABP Studio's *[Solution Explorer](../../studio/solution-explorer.md)*:
 
@@ -28,10 +32,10 @@ Initially, you see a `ModularCrm` solution and a `ModularCrm` module under that
 
 > An ABP Studio module is typically a .NET solution and an ABP Studio solution is an umbrella concept for multiple .NET Solutions (see the [concepts](../../studio/concepts.md) document for more).
 
-`ModularCrm` module is your main application, which is a layered .NET solution that consists of several packages (.NET projects). You can expand the `ModularCrm` module to see its packages:
+The `ModularCrm` module is the core of your application, built as a single-layer ASP.NET Core Web application. You can expand the `ModularCrm` module to see:
 
 ![solution-explorer-modular-crm-expanded](images/solution-explorer-modular-crm-expanded.png)
 
 ## Summary
 
-We've created the initial layered monolith solution. In the next part, we will learn how to create a new application module and install it to the main application.
+We've created the initial single layer monolith solution. In the next part, we will learn how to create a new application module and install it to the main application.