Create a legend on the map

Hello everyone, I have a problem with obtaining a legend on the map that presents the "worldmap" node. I have accessed the document: "node-red-contrib-web-worldmap 2.37.4" and in its "command" section it says to obtain the legend: "(To add and remove a legend
If you want to add a small legend overlay

msg.payload.command = { "legend": "Title
<i style="background: #477AC2"> Water
<i style=\ "background: #448D40">Forest
" };
To remove set the legend to an empty string ."")". dedicating a function node to it and applying the message, I can't see the example.
Could someone help me? How should I compose the message? I don't know JSON very well.
Thank you

Here is that example as a flow

[{"id":"580d66cc9df1f9f5","type":"inject","z":"abdd6f69c1e320b7","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"str","x":130,"y":180,"wires":[["b76750ca4e7343c9"]]},{"id":"b76750ca4e7343c9","type":"function","z":"abdd6f69c1e320b7","name":"function 1","func":"msg.payload ={};\nmsg.payload.command = { \"legend\": \"<b>Title</b></br><i style=\\\"background: #477AC2\\\"></i> Water<br><i style=\\\"background: #448D40\\\"></i> Forest<br>\" };\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":320,"y":180,"wires":[["59a42f2604899c31"]]},{"id":"59a42f2604899c31","type":"worldmap","z":"abdd6f69c1e320b7","name":"","lat":"","lon":"","zoom":"","layer":"","cluster":"","maxage":"","usermenu":"show","layers":"show","panit":"false","panlock":"false","zoomlock":"false","hiderightclick":"false","coords":"false","showgrid":"false","showruler":"false","allowFileDrop":"false","path":"/worldmap","overlist":"DR,CO,RA,DN,HM","maplist":"OSMG,OSMC,EsriC,EsriS,EsriT,EsriDG,UKOS","mapname":"","mapurl":"","mapopt":"","mapwms":false,"x":520,"y":180,"wires":[]}]

Hello and thank you very much for giving me a hand so soon. I see that you have described the complete FLOW to me, thank you very much.
Jaime