An approach that I've taken is to integrate Tasker with other tools that already do reminders.
So for example, the free version of the Memento database provides an action that allows for sending data to a local personal database. Entries/records in a database can contain any kind of data. For this application I tell Tasker "Hey tasker, take a note." It responds "What's the subject?", and I speak a simple subject. Then it asks "And what's the note?" So I dictate a very brief note, because at this point it gets confused about how long to keep the microphone active. The audio is transcribed to text and saved in a new record.
Now, Memento supports reminders as well, which can be set through the Tasker action. I do not have this enabled but it would be easy to have it ask "Set a reminder?", get a response, convert that to text, and then add that in to the Memento action that creates the database record.
Putting this all together, a Profile triggers a task that requests a voice message, converts that to text, then saves the text to Memento with a reminder.
You don't need the voice part, you can tap a shortcut to open Tasker with an input dialog, and then just enter the text.
My project also accepts requests like "save my location". After I
save put text into the clipboard I can say "save that text", which then
goes into a different Memento database. And "save that URL" saves the
clipboard buffer in a Link field rather than plain text.
You don't actually need Memento. Find any app that saves reminders. Or use an action that creates a Google Calendar item. Or send yourself an Gmail that has date/time info, which Google auto-converts to Calendar items. Or see if you can send an Intent to your SMS app which schedules a message.
There are many ways to approach this. Just think through each
action that is required. There aren't many. You can even load the heavy
duty project that you linked and hack out everything that you don't
want. If your intent here is that you don't know how to get Tasker to do things ... that's fine, hacking up an existing project would be a great way to learn how someone else does it.
I'm hesitent to share my project because there might be personal details in there - I simply don't remember. Joao also posted a note recently that Google is ending support for the voice services that may underpin my application as described here. I haven't looked at the details yet. But my project is as heavy duty as the other one, so I'm hoping you'll follow the guidance here rather than relying on specific code.