Add suggestion to transfer downloaded checkpoints and rename filenames (

#758)

* Add suggestion to transfer and rename checkpoints

* Remove extra spaces

doc/faq.md

@@ -53,6 +53,23 @@ The PyPI page for `micro-sam` exists only so that the [napari-hub](https://www.n
 ### 7. I get the following error: `importError: cannot import name 'UNETR' from 'torch_em.model'`.
 It's possible that you have an older version of `torch-em` installed. Similar errors could often be raised from other libraries, the reasons being: a) Outdated packages installed, or b) Some non-existent module being called. If the source of such error is from `micro_sam`, then `a)` is most likely the reason . We recommend installing the latest version following the [installation instructions](https://github.com/constantinpape/torch-em?tab=readme-ov-file#installation).
 
+### 8. My system does not support internet connection. Where should I put the model checkpoints for the `micro-sam` models?
+We recommend transferring the model checkpoints to the system-level cache directory (you can find yours by running the following in terminal: `python -c "from micro_sam import util; print(util.microsam_cachedir())`). Once you have identified the cache directory, you need to create an additional `models` directory inside the `micro-sam` cache directory (if not present already) and move the model checkpoints there. At last, you **must** rename the transferred checkpoints as per the respective [key values](https://github.com/computational-cell-analytics/micro-sam/blob/master/micro_sam/util.py#L87) in the url dictionaries located in the `micro_sam.util.models` function (below mentioned is an example for Linux users).
+
+```bash
+# Download and transfer the model checkpoints for 'vit_b_lm' and `vit_b_lm_decoder`.
+# Next, verify the cache directory.
+> python -c "from micro_sam import util; print(util.microsam_cachedir())"
+/home/anwai/.cache/micro_sam
+
+# Create 'models' folder in the cache directory
+> mkdir /home/anwai/.cache/micro_sam/models
+
+# Move the checkpoints to the models directory and rename them
+# The following steps transfer and rename the checkpoints to the desired filenames.
+> mv vit_b.pt /home/anwai/.cache/micro_sam/models/vit_b_lm
+> mv vit_b_decoder.pt /home/anwai/.cache/micro_sam/models/vit_b_lm_decoder
+```
 
 ## Usage questions