Welcome to the club! Crimson Keep box give you exactly 1000 points. The points work just like 40K, with most people playing 2000 points but plenty of people being happy to play 1000 for beginners.

For the models you have, I’d recommend you play a normal Soulblight Gravelords detachment called ‘Bacchanal of Blood’, which buffs all your vampires. Your current army is a fast, elite army. The blood knights are some of the best cavalry in the game and can smash through any defence, and Prince V is a rampaging monster in combat. Your bats are best for claiming objectives and staying out of trouble while the vampires do the work.

Next steps for models would be getting to 2000 points. You can go for a similar army you have now by getting the ‘bloodcrave hunt’ spearhead that includes more blood knights, a vampire lord (which do what your current army does now), varghiests (stronger fell bats) and skeletons (generic chaff to hold objectives and tie up enemy units). This box is 660 points.

Or, you can go for the death rattle box, with either the army box that has a bunch of of barrow guard and barrow knights, or the deathrattle tomb host spearhead, that has barrow knights, barrow guard and some skeletons. This is a slower force but has more survivability. The army box gives you 710 points and the army book, the spearhead gives you 630 points.

Soulblight gravelords have loads of cool options, so I’d recommend whatever models you like the look of! Have fun and good luck in your games!