Docs: Rearrange TF-M building instructions

- move the building instructios to a dedicated folder, reflecting main TOC
- adjust links in the documentation

Signed-off-by: Anton Komlev <anton.komlev@arm.com>
Change-Id: I335de95061938d619a47cd813020121809e1459b
diff --git a/docs/getting_started/tfm_getting_started.rst b/docs/getting_started/tfm_getting_started.rst
index 128b05a..dad3dc6 100644
--- a/docs/getting_started/tfm_getting_started.rst
+++ b/docs/getting_started/tfm_getting_started.rst
@@ -25,9 +25,9 @@
 
     - Follow the this guide to set up and check your environment.
     - Follow the
-      :doc:`Build instructions </technical_references/instructions/tfm_build_instruction>`
+      :doc:`Build instructions </building/tfm_build_instruction>`
       to compile and build the TF-M source.
-    - Follow the :doc:`Run TF-M examples on Arm platforms </technical_references/instructions/run_tfm_examples_on_arm_platforms>`
+    - Follow the :doc:`Run TF-M examples on Arm platforms </building/run_tfm_examples_on_arm_platforms>`
       for information on running the example.
 
 To port TF-M to a another system or OS, follow the
@@ -454,10 +454,10 @@
 
 Here are some next steps for exploring TF-M:
 
-    - Detailed :doc:`Build instructions </technical_references/instructions/tfm_build_instruction>`.
-    - :doc:`IAR Build instructions </technical_references/instructions/tfm_build_instruction_iar>`.
-    - Try other :doc:`Samples and Demos </technical_references/instructions/run_tfm_examples_on_arm_platforms>`.
-    - :doc:`Documentation generation </technical_references/instructions/documentation_generation>`.
+    - Detailed :doc:`Build instructions </building/tfm_build_instruction>`.
+    - :doc:`IAR Build instructions </building/tfm_build_instruction_iar>`.
+    - Try other :doc:`Samples and Demos </building/run_tfm_examples_on_arm_platforms>`.
+    - :doc:`Documentation generation </building/documentation_generation>`.
 
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