Learndash Landpage Login Popup Button/Course Enrollment/Redirect

I have created a landing page for free piano lessons. The lessons are here https://straightforwardpiano.com/courses/the-fyodor-method-free-trial-course/ But I do not ever want people to see this cheap-looking learndash page. If you aren’t familiar with how the page works, it sends them to that page I do not want unless they are…
1. Logged in
2. Enrolled in that course
Once these 2 conditions are met, they are taken inside to a page which shows them the list of lessons where they can then click one and finally be taken into the course.

I want this entire process to be skipped. I need to figure out how to add a learndash login popup/or any login/register popup, which would then allow them to create an account. From there, while they are still on the landing page, I want a button that will appear (to logged-in users only), that will do 2 things at the same time….
1. Enroll the user into this specific course
2. redirect them directly inside of the course to this URL https://straightforwardpiano.com/courses/the-fyodor-method-free-trial-course/lessons/what-you-need-to-get-started-2/

What I set up:
I have made it so that there are 2 buttons on the page visible and not visible based on log In conditions.

What I need:
1. I need a link that will bring up the learndash popup inside of the landing page
2. I need a link that will enroll the user into this specific course and simultaneously redirect them here https://straightforwardpiano.com/courses/the-fyodor-method-free-trial-course/lessons/what-you-need-to-get-started-2/

It is very important that they go from this landing page directly into the course and nowhere else in between. Basically, we want to go from point A to D, without going to points B and C.

Can you get me those links?

The page I need help with: [log in to see the link]