rename and extend README file and start using markdown.

macro/trd/README

-----------------------------------------------------------------------------------
------                                 README                                 -----
------                           cbmroot/macro/trd                            -----
------     Created : 16/12/2005                                               -----
------ Last update : 03/06/2013                                               -----
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-
-
-# how to create a .digi.par file from a geometry
-# copy trd_v13x.root to macro/trd/geometry
-cp geometry/trd.v13/trd_v13x.root geometry
-./create_digipar_root.sh
-
-# run simulation in macro/trd
-root -l run_sim.C
-root -l run_reco.C
-root -l eventDisplay.C 
-
-# standard file contains only 5 events for run_sim:
-cbmroot_trunk/input/urqmd.ftn14
-
-# if you need more, get urqmd.auau.25gev.centr.0000.ftn14
-# from here
-http://cbm-wiki.gsi.de/cgi-bin/view/Computing/CbmDataUrQMD13
-# and link it to
-cbmroot_trunk/input/
-
-
-#=============================================================
-# old comments below
-#=============================================================
-
-macros in TRD directory:
-
-                sim.C - makes the transport of UrQMD events. Output files are
-   	                test.mc.root and test.mc.param.root
-		Sts.C - runs reconstruction in the STS. Output file is
-		        test.stsTracks.root
-  CbmTrdHitProducer.C - produces TRD hits from TRD points. Output file is
-                        test.trdHits.root
-TrdTrackFinderIdeal.C - runs ideal TRD track finder and Kalman Filter
-                        track fitter together with performance tasks.
-			Output file is test.trdIdealTracks.root
-  TrdTrackFinderSts.C - runs TRD track finder, based on track following
-  			from STS approach. Found tracks are fitted
-			using the Kalman Filter fitter. Output file is
-			test.trdTracks.root
-
-

macro/trd/README.md

+[//]: # -----------------------------------------------------------------------------------
+[//]: # -----                                 README                                 -----
+[//]: # -----                           cbmroot/macro/trd                            -----
+[//]: # -----     Created : 16/12/2005                                               -----
+[//]: # ----- Last update : 16/11/2021                                               -----
+[//]: # -----------------------------------------------------------------------------------
+
+
+# Summary
+1. [Generating the parameter files](#generating-the-parameter-files-from-a-geometry)
+2. [Simulation](#run-simulation-in-macro/trd)
+3. [TRD macros](#trd-macros)
+
+## Generating the parameter files from a geometry
+The following ordered steps should be performed in order to produce the parameter files for the TRD system. All files and directories are given relative to the CbmRoot source directory.
+
+1. Run the create geometry macro. Examples of such macro can be found in  **macro/trd/geometry/trd.v??** or **macro/mcbm/geometry/trd** and are named **Create_TRD_Geometry_[tag].C** where tag is a unique identifier of the geometry. Examples are tag = "v22a_mcbm". The following files will be created by the previous procedure:
+    1. trd_[tag].geo.info;
+    2. trd_[tag].geo.root;
+    3. trd_[tag]_geo.root;
+    4. CbmTrdPads_[tag].h;
+2. Copy the first two files **geometry/trd**. In the case when the geometry of the pad-plane is not of a default type as implemented in **core/detectors/trd/CbmTrdPads.h** replace also this file with the one newly generated CbmTrdPads_[tag].h.
+3. Compile the code by running **make install** on your build directory
+4. Execute **macro/trd/create_digipar_root.sh tag**. The following **four** files will be created: 
+    - trd_[tag].asic.par
+    - trd_[tag].digi.par
+    - trd_[tag].gain.par
+    - trd_[tag].gas.par
+5. Move these files to the **parameters/trd** directory and execute item **3.** again.    
+    
+## Run simulation in macro/trd
+- root -l run_sim.C
+- root -l run_reco.C
+- root -l eventDisplay.C 
+
+Standard file contains only 5 events for run_sim in **input/urqmd.ftn14**. If you need more, get urqmd.auau.25gev.centr.0000.ftn14
+from [here](http://cbm-wiki.gsi.de/cgi-bin/view/Computing/CbmDataUrQMD13) and link it to the input directory.
+
+
+[//]: # =============================================================
+[//]: # old comments below
+[//]: # =============================================================
+
+## TRD macros
+
+| Macro name | Description |
+| -------- | ------------- |
+| sim.C | makes the transport of UrQMD events. Output files are
+   	                test.mc.root and test.mc.param.root |
+		Sts.C - runs reconstruction in the STS. Output file is
+		        test.stsTracks.root
+  CbmTrdHitProducer.C - produces TRD hits from TRD points. Output file is
+                        test.trdHits.root
+TrdTrackFinderIdeal.C - runs ideal TRD track finder and Kalman Filter
+                        track fitter together with performance tasks.
+			Output file is test.trdIdealTracks.root
+  TrdTrackFinderSts.C - runs TRD track finder, based on track following
+  			from STS approach. Found tracks are fitted
+			using the Kalman Filter fitter. Output file is
+			test.trdTracks.root
+
+