Understanding how to properly save an animation

So I was working on a solo build challenge that I made it to challenge my building skills
Here’s the progress if you guys wanna see it:-

Phone Showcase/Shop

As you can see, there’s a rig there. Now I’m attempting to animate the rig to be as if its sitting down on a chair, both hands laid on the table, left arm to hand bend and put to head; right arm, welp just laid right there

Something like this I wanna animate it in idle position:-

I did kinda, well, uploaded to Roblox as my first ever animation, but I’m not if I did it right

Link: Idle Bored - Roblox

My issue is: How do you actually properly save and export an animation to Roblox and then able to use it for my builds

I’m not achieving it by the scripting way btw

I’m dang new to animating, so please help a friend out :slight_smile: