figuring out how to ling stuff

ICON-NWP/how-to-bacy.md

+This is a small guide on how to use bacy to run assimilation cycles in practice.
+
+## Prerequisites
+Before running you need:
+* a path to a directory containing a bacy with initial conditions for your experiment
+* a icon gridfile, a radiation gridfile and extpar-Data. You can create these using the `icongridgenerator`
+or via the [web](https://webservice.dwd.de/cgi-bin/spp1167/webservice.cgi) interface at DWD (user icon-web, pw: icon@dwd).
+* a working bacy, cloned eihter from [`git@gitlab.dkrz.de:dace/dace_bacy.git`](./bacy.md#How to get BACY_1.0?) or from another bacy using `bacy_clone.sh`