How to restore root subvolume BTRFS snapshot?

I'm using CachyOS (Arch) with BTRFS. And tried to restore snap of root subvolume and it didn't work ( see previous post ).

If I remember correctly, i successfully restored root subvolume before. Take it with a grain of salt.

Some people on my previos posts said that I shouldn't have tried restore root subvol while system is actively running through the subvol.

Now my question is,

How to restore a snap of root subvolume ?

Edit: I know how to restore a snapshot. Just need help with root subvol snapshot.

I use BTRFS Assistant with snapper. And rEFInd doens't have boot to snapshot option. (I installed and it didn't work )