added a warning about submitting to cuda-zen in the Using GPUs page

docs/running_jobs/gpus.md

@@ -24,6 +24,30 @@ module purge
 module load cuda/9.1.85
 ``` 
 
+!!! Warning
+    **You must submit the GPU job in the correct partition!**<br>
+    Sumbit your GPU jobs in the cuda-zen partition <br>
+    In VSC-5: <br>
+    zen partition for CPU jobs<br>
+    cuda-zen partition for GPU jobs<br>
+    This allows to load the correct modules.
+
+    To avoid errors, directly specify the module tree with the `spackup` command  in the submission script, for example:
+    ```
+    #!/bin/bash
+    #SBATCH --partition=zen2_0256_a40x2
+    #SBATCH --qos=zen2_0256_a40x2
+    #SBATCH -J cp2k_test
+    #SBATCH --gres=gpu:1
+    #SBATCH -t 00:05:00
+
+    spackup cuda-zen
+    module load cp2k/master-gcc-11.4.0-nmxvrkm
+
+    mpirun -n 2 cp2k.popt -i argon.inp
+
+    ``` 
+
 The command ```nvidia-smi```, the output of which shown below, is used to look at the state of the GPU cards on the system. An example is shown below for the A100 card, with no jobs running. When under use, the GPU Memory Usage as well as GPU-Util metrics will increase accordingly, and is also an effective tool to judge if the application/code is utilizing the GPU or not. 
 
 === "nvidia-smi - A100"