add explanations to the text-seg task

README.md

@@ -63,6 +63,10 @@ imgs = npz[‘imgs’]
 print(npz[‘text_prompts’])
 ```
 
+Remarks:
 
+1. To ensure rotation consistency, all testing cases will be preprocessed to standard rotation by https://nipy.org/nibabel/reference/nibabel.funcs.html#nibabel.funcs.as_closest_canonical
+2. Some datasets don't have text prompts, please simply exclude them during model training.
+3. For instance labels, the evaluate metric is [F1 score](https://github.com/JunMa11/NeurIPS-CellSeg/blob/main/baseline/compute_metric.py) where the order of instance id doesn't matter.