cards created by Beacon of the Reach retain the link if they're transformed, so transforming them into sigils and playing them will still generate a new card for you to use to keep going, and additionally provide power and influence you need to play more Beacon of the Reach cards later. this allows you to bank on the early game power of the plunder cards to defend or ramp and power up. Beacon of the Reach essentially scales off your influence and power since you can just keep churning out cards.
The ShiftstonedEternal Power Calculator is a deck-building tool that visualizes your odds of drawing enough Influence and Power based specifically on the cards found in your deck.
I've spent like 10 games trying to not die while getting all the influence in place and getting the Beacon out, but I've only been able to play a single card off of it. Interesting, but not working super well, lol
you'll usually need to plunder for 1 or 2 of the influence to get the beacon out initially, but shouldn't be that difficult. you also only need the base 1 of each for the most part since you can plunder the cards it's generating. you'll need to prioritize the order you get the influence based on the situation though. usually it'll be time for ramp/influence or green for defense as top priorities, then purple and blue for defense, and red last