Update README; add instructions

README.md

 # e3-autosave
 
-## Preparation of DB
+Wrapper for the `autosave` module - part of EPICS infrastructure at ESS. This module is loaded through `essioc` for production IOCs.
 
-Each record in database file that needs to have values saved by `autosave` must have the one of following `info` tags. Such as
+## Installation
+
+```sh
+$ make init patch build
+$ make install
 ```
- info(autosaveFields, "PREC SCAN DESC OUT")
- info(autosaveFields_pass0, "VAL")
- info(autosaveFields_pass1, "VAL")
+
+For further targets, type `make`.
+
+## Usage
+
+```sh
+$ iocsh -r "autosave"
 ```
 
-Each info tag should be matched with what one would like to use such as
+### How it works
+
+To set up autosave (and boot-time restore) of record fields, use one of the following info-tags:
 
-* `autosaveFields` : before and after record initialization
-  - `settings.sav` : in `$(AS_TOP)/$(IOCNAME)/save`
-  - `settings.req` : in `$(AS_TOP)/$(IOCNAME)/req`
+* `autosaveFields`: to restore **before** and **after** record initialization
+  - `settings.sav`: in `$(AS_TOP)/$(IOCNAME)/save`
+  - `settings.req`: in `$(AS_TOP)/$(IOCNAME)/req`
  
-* `autosaveFields_pass0` : before record initialization
-  - `values_pass0.sav` : in `$(AS_TOP)/$(IOCNAME)/save`
-  - `values_pass0.req` : in `$(AS_TOP)/$(IOCNAME)/req`
+* `autosaveFields_pass0`: to restore only **before** record initialization
+  - `values_pass0.sav`: in `$(AS_TOP)/$(IOCNAME)/save`
+  - `values_pass0.req`: in `$(AS_TOP)/$(IOCNAME)/req`
+
+* `autosaveFields_pass1`: to restore only **after** record initialization
+  - `values_pass1.sav`: in `$(AS_TOP)/$(IOCNAME)/save`
+  - `values_pass1.req`: in `$(AS_TOP)/$(IOCNAME)/req`
+
+For example:
+
+```
+record("*", "some-record") {
+    info(autosaveFields, "PREC SCAN DESC OUT")
+    info(autosaveFields_pass0, "VAL")
+    info(autosaveFields_pass1, "VAL")
+}
+```
+
+Each info tag should be matched with what one would like to use such as
+
+## Contributing
 
-* `autosaveFields_pass1`: after record initialization (Most autosave values can be restored at Pass 0 and Pass 1 using the `autosaveFields` info tag.)
-  - `values_pass1.sav`    : in `$(AS_TOP)/$(IOCNAME)/save`
-  - `values_pass1.req`    : in `$(AS_TOP)/$(IOCNAME)/req`
+Contributions through pull/merge requests only.