Fix GPU example

docs/using-gpus.md

@@ -14,7 +14,7 @@ CUDA is available as a module:
 $ module load CUDA
 ```
 
-This example is executed on the JUWELS booster module.
+This example is executed on the JUWELS booster module. If you plan to use a different JSC system, ensure that you select a partition with GPUs.
 To demonstrate how to compile and run a program that uses GPUs, we will use one of the examples included in CUDA.
 To do this, we must additionally load the compiler `NVHPC` and the MPI version `ParaStationMPI`.  
 Additionally, we load a settings module that ensures our MPI implentation is properly set up to use CUDA.  
@@ -26,7 +26,7 @@ We load the necessary modules, navigate into our individual user directories for
 ```
 $ module load NVHPC ParaStationMPI MPI-settings/CUDA
 $ cd $PROJECT_trainingFIXME/$USER
-$ git clone https://github.com/NVIDIA/cuda-samples.git
+$ git clone --depth 1 -b v12.5 https://github.com/NVIDIA/cuda-samples.git
 $ cd $PROJECT_trainingFIXME/$USER/cuda-samples/Samples/0_Introduction/simpleMPI
 $ make
 /p/software/jurecadc/stages/2024/software/psmpi/5.9.2-1-NVHPC-23.7-CUDA-12/bin/mpicxx -I../../../Common    -o simpleMPI_mpi.o -c simpleMPI.cpp