add helper text to Localities tab when creating a new museum

frontend/src/components/Museum/MuseumDetails.tsx

@@ -26,7 +26,7 @@ export const MuseumDetails = () => {
     },
     {
       title: 'Localities',
-      content: <LocalityTab />,
+      content: <LocalityTab isNew={isNew} />,
     },
   ]
 

frontend/src/components/Museum/Tabs/LocalityTab.tsx

@@ -2,7 +2,7 @@ import { SimpleTable } from '@/components/DetailView/common/SimpleTable'
 import { useDetailContext } from '@/components/DetailView/Context/DetailContext'
 import { MuseumLocalities } from '@/shared/types'
 
-export const LocalityTab = () => {
+export const LocalityTab = ({ isNew }: { isNew: boolean }) => {
   const { data } = useDetailContext<MuseumLocalities>()
 
   const columns = [
@@ -23,7 +23,12 @@ export const LocalityTab = () => {
       header: 'Min Age',
     },
   ]
-  if (!data) return <div>No localities</div>
+  if (isNew)
+    return (
+      <div>
+        Link localities to this museum after finalizing it by editing a locality and navigating to the museum tab there.
+      </div>
+    )
 
   return <SimpleTable columns={columns} data={data.localities} idFieldName="lid" url="locality" />
 }