[NESTED] guide: Exp implementation details, naming into Overview (#3006)

* guide: bring exp implementation details and naming from ref.
per #2909 (review)

* guide: copy edits to exp naming info.

content/docs/command-reference/exp/run.md

@@ -32,36 +32,25 @@ data and code updates, or <abbr>hyperparameter</abbr> tuning. For the latter,
 you can use the `--set-param` (`-S`) option of this command to change
 `dvc param` values on-the fly.
 
-Each experiment creates and tracks a project variation based on your
-<abbr>workspace</abbr> changes. Experiments will have an auto-generated name
-like `exp-bfe64` by default, which can be customized using the `--name` (`-n`)
-option.
+📖 See [DVC Experiments Overview][exp-overview] for more information.
 
-<details>
-
-### ⚙️ How does DVC track experiments?
-
-Experiments are custom
-[Git references](https://git-scm.com/book/en/v2/Git-Internals-Git-References)
-(found in `.git/refs/exps`) with a single commit based on `HEAD` (not checked
-out by DVC). Note that these commits are not pushed to Git remotes by default
-(see `dvc exp push`).
-
-</details>
-
-The results of the last `dvc exp run` can be seen in the workspace. To display
-and compare multiple experiments, use `dvc exp show` or `dvc exp diff`
-(`plots diff` also accepts experiment names as `revisions`). Use `dvc exp apply`
-to restore the results of any other experiment instead.
+Each experiment creates and tracks a project variation based on the changes in
+your <abbr>workspace</abbr>. The results of the last `dvc exp run` will be
+reflected in the workspace. Experiments will have an auto-generated ID like
+`exp-bfe64` by default. A custom name can be given instead, using the `--name`
+(`-n`) option
 
-Successful experiments can be made [persistent] by committing them to the Git
-repo. Unnecessary ones can be removed with `dvc exp remove`or `dvc exp gc` (or
-abandoned).
+To display and compare multiple experiments, use `dvc exp show` or
+`dvc exp diff` (`plots diff` also accepts experiment names as `revisions`). Use
+`dvc exp apply` to restore the results of any experiment, for example to [commit
+them][persisting] to Git. Unnecessary experiments can be removed with
+`dvc exp remove`or `dvc exp gc` (or abandoned).
 
-> Note that experiment data will remain in the <abbr>cache</abbr> until you use
-> regular `dvc gc` to clean it up.
+> Note that experiment data will remain in the local <abbr>cache</abbr> until
+> you use regular `dvc gc` to clean it up.
 
-[persistent]: /doc/user-guide/experiment-management/persisting-experiments
+[exp-overview]: /doc/user-guide/experiment-management/experiments-overview
+[persisting]: /doc/user-guide/experiment-management/persisting-experiments
 
 ## Checkpoints
 

content/docs/user-guide/experiment-management/experiments-overview.md

@@ -1,10 +1,29 @@
 # DVC Experiments Overview
 
-DVC Experiments are captures automatically by DVC when you [run them].
+DVC Experiments are captures automatically by DVC when you [run them]. Each
+experiment creates and tracks a project variation based on the changes in your
+<abbr>workspace</abbr>. Experiments preserve the latest commit in the current
+branch (Git `HEAD`) as their parent or _baseline_.
+
+<details>
+
+### ⚙️ How does DVC track experiments?
+
+Experiments are custom [Git references] (found in `.git/refs/exps`) with a
+single commit based on `HEAD` (not checked out by DVC). Note that these commits
+are not pushed to Git remotes by default (see `dvc exp push`).
+
+</details>
+
+Experiments will have an auto-generated ID like `exp-bfe64` by default. A custom
+name can be given instead (using the `--name`/`-n` option of `dvc exp run`).
+
+> ID or name can be used to reference experiments with `dvc exp` subcommands.
 
 [run them]: /doc/user-guide/experiment-management/running-experiments
+[git references]: https://git-scm.com/book/en/v2/Git-Internals-Git-References
 
-## Basic Workflow
+## Basic workflow
 
 `dvc exp` commands let you automatically track a variation to a committed
 project version (baseline). You can create independent groups of experiments