chore: add details for signed create finality provider

app/upgrades/signetlaunch/README.md

@@ -30,10 +30,9 @@ with some simple bash script:
 
 ```shell
 GO_BTC_HEADERS_PATH="signetlaunch/data_btc_headers.go"
-btcBlockTipHeight=1000
 EXPORT_TO="./btc-headers.json"
 # export the btc headers to a file
-$SID_BIN btc-headers 1 $btcBlockTipHeight --output $EXPORT_TO
+$SID_BIN btc-headers 1 1000 --output $EXPORT_TO
 btcHeadersJson=$(cat $EXPORT_TO)
 
 # writes the headers to babylon as go file
@@ -42,4 +41,19 @@ echo "package signetlaunch
 const NewBtcHeadersStr = \`$btcHeadersJson\`" > $GO_BTC_HEADERS_PATH
 ```
 
-### Signed Create
+### Signed Create Finality Provider
+
+For BTC stakers to stake during Phase-1 it is needed to have finality
+providers. Babylon created a repository to publicly store this information
+inside [networks](https://github.com/babylonlabs-io/networks) repository.
+Inside the bbn-1 mainnet all the finality providers that wanted to be available
+for BTC staking since the beginning would need to
+[register](https://github.com/babylonlabs-io/networks/blob/main/bbn-1/finality-providers/README.md)
+theirselves in the registry.
+For the transition from Phase-1 to Phase-2, registered finality providers in
+Phase-1 will need to provider a signed
+[MsgCreateFinalityProvider](../../../x/btcstaking/types/tx.pb.go#38) as a
+json file message inside the networks repository registry.
+
+<!-- TODO: shell to generate the string message with signed finality
+providers from the networks repository -->