first, the partial

layouts/partials/series_header.html

@@ -0,0 +1,20 @@
+{{- with index (.GetTerms "series") 0 -}}
+<div class="post-series notice--info">
+        <h3 id="series">This post is part of the <a href="{{ .Permalink }}" style="font-weight: bold">{{ .LinkTitle }}</a> series.</h3>
+
+    {{- end -}}
+    {{- $series := where .Site.RegularPages.ByDate ".Params.series" "intersect" .Params.series -}}
+    {{- with $series -}}
+            <ol>
+                {{- range . -}}
+                <li>
+                    {{- if eq .File.UniqueID $.File.UniqueID -}}
+                    <b>{{ .Title }}</b>
+                    {{- else -}}
+                    <a href="{{ .Permalink }}">{{ .Title }}</a>
+                    {{- end -}}
+                </li>
+                {{- end -}}
+            </ol>
+    {{- end -}}
+</div>