Just to note, first boot on AM5 can take awhile so don't panic if things don't immediately happen. The system will power up and you'll see fans spinning etc, but it could take as long as 15-20 mins before things start moving.
Booting up after that point will be more in line with what you're used to with other systems, the first time you do with AM5 it needs to figure out how to use your RAM.
There's a few good video guides out there for AM5 that might be helpful to you, but otherwise take your time and just enjoy the process.
@ben1987 advising to install a lot of the components prior to putting things in the case is excellent advice, pop the motherboard on a clean wood surface or even just on top of the box it came in (do not put the anti-static bag under it).
With the Phantom Spirit heatsink, what I'd personally do is install the mounting bracket as per the instructions and then after you've put the motherboard in the case and all other components/wiring etc are in place mount the big lumpy tower cooler to the bracket.
Frankly, people go wild about the perfect way to apply paste but for 98% of users it doesn't matter as long as there's enough coverage between the IHS/CPU and heatsink.