How do I trim his nails?

Got my cat from my brother who was a shitty cat owner. Cat’s relatively large, too strong for me to risk holding him down in case he hurts himself, and he’s not desensitized to most things because my brother thought he was part savannah, and wanted him to “stay wild”.
I don’t wanna give him up because he’s been through a lot, and he’s grown attached to me and I to him, but his claws are getting out of hand.
We have two other cats that we’ve had since they were 2 months, so no issues with trimming/grooming.
However, one of them has bad scarring on her eyes that makes it hard to defend herself when the other cat gets aggressive, and the other is timid and doesn’t really fight back.
I don’t wanna give him up, and a groomer/vet visit isn’t in the cards financially right now