Update USE_EXISTING_DATA.md to latest test links, add reference to other ways of exploring

Author: jfy133

docs/USE_EXISTING_DATA.md

@@ -2,6 +2,10 @@
 
 Please fill in the appropriate checklist below (delete whatever is not relevant). These are the most common things requested when adding a new test dataset.
 
- - [ ] Check [here](https://github.com/nf-core/test-datasets/branches/all) to find the branch corresponding to the test dataset you want to use
- - [ ] Specify in the `conf/test.config` the path to the files from the test dataset
- - [ ] Set up your CI tests following the nf-core best practices (cf [.github/workflows/ci.yml template](https://github.com/nf-core/tools/blob/dev/nf_core/pipeline-template/.github/workflows/ci.yml))
+ - [ ] Check [here](https://github.com/nf-core/test-datasets/branches/all) to find the branch corresponding to the test dataset you want to use (i.e., `modules`, or a given pipeline)
+   - [ ] Alternatively use nf-core tools to search and explore, e.g. `nf-core test-datasets list` (press tab for options), and then `nf-core test-datasets search -b modules fasta` (press tab for options)
+   - [ ] You can also use the flag `--generate-nf-path` to generate config ready strings
+ - [ ] Specify in the `conf/test.config` the path to the files from the test dataset 
+ - [ ] Set up your CI tests following the nf-core best practices
+   - [ ] For pipelines: [tests/default.nf.test](https://github.com/nf-core/tools/blob/main/nf_core/pipeline-template/tests/default.nf.test))
+   - [ ] For modules: [tests/main.nf.test](https://github.com/nf-core/tools/blob/main/nf_core/module-template/tests/main.nf.test.j2)