Side note: It’s a whole lot easier if you copy/paste the code related to those models into the body of your post. When doing so, enclose the code (or template) between lines of three backtick - ` characters. This means you’ll have a line of ```, then your code (or template), then another line of ```. This forces the forum software to keep your code properly formatted.
This is a topic that has been discussed here in the forum in multiple locations. Some threads you may wish to read include:
(There are probably more - these are just ones that I remember as potentially being the most useful.)
A key point to remember is that you can render multiple forms in the same template. You can then do whatever processing is necessary when saving those forms.
You may also want to review the docs and examples at the save method.