Ramjee,
The raw power for your new fuse block will have to come from the battery, there’s no way around that. That and your trickle charge SAE plug (I’m assuming) need to be added to the battery terminals.
The ‘signal’ that wakes up the fuse block is looking for 12V, and that’s the wire that I tapped in my previous thread (stop/horn). Pics were included in that post. This is a tiny 12V draw that simply activates a relay switch inside your new fuse block and won’t be noticed on whatever circuit it’s on.
My bike is a 2020, but look at your motorcycle’s fuse box and find the wire that come out the bottom from your fuse box for horn/stop or similar key-activated power. The fuse box lifts up so this wire should be very easy to get to. My pics in the other thread show this. This is much easier than working at the rear of the bike and bringing the tail light signal back to the new fuse block.
You new fuse block should have included the ‘tap’ that will cut through the insulation sheath on both the small trigger wire and the wire you will use as a switched signal. Using this is helpful as you don’t have to cut anything.
Close the plastic tap case very tightly to make sure you get good electrical contact on both wires.
Regarding the 10A fuse, the fuses don’t determine the load, it’s simply a total of loads that you install that pull current. To insure that you don’t accidentally overload the new block, you can pull the 5’s and install a 10A, 5A, 3A, and a 2A and hold the 5’s as emergency spares. Remember, these are low-profile minis.