three compounds (test, NPP, anavar) for a first cycle is a lot of variables to start with. NPP especially hits harder on suppression and prolactin, and first-timers often aren't ready for that. If something goes wrong, you won't even know which compound caused it.
If you're going ahead regardless, pay attention to: bloodwork before and during the cycle (lipids, liver, hematocrit, hormones), a PCT plan already sourced and ready, not something you'll sort out later, and knowing the symptoms of prolactin or estrogen issues so you catch problems early

Test only bro

Test only, brother.

I’d strongly suggest your first 2 to 4 cycles be testosterone only. You can build an incredible physique with just test, and it lets you learn how your body responds before you start adding variables.

You may or may not need an AI, but I’d definitely have one on hand. Don’t take it preemptively. Only use it if bloodwork and symptoms indicate you need it. You don’t want estrogen related side effects and nothing available to manage them.

As for your math, assuming the vials are accurately dosed, two 10 mL vials of 250 mg/mL Test C gives you 5,000 mg total. That’s about 16.7 weeks at 300 mg/week or 20 weeks at 250 mg/week, so you’ve got plenty for a first cycle.

Most beginners start somewhere in the 200 to 400 mg/week range, with 12 to 16 weeks being a common first cycle length. Get baseline bloodwork before you start, repeat it during and after the cycle, and have your PCT planned before your first injection, not after.

Shredski dropped a line to the newbie sections. I recommend you spend a few hours reading around the site and use the search box at the top, almost every question you will think of has been answered.

Test only

First cycle should be test only as @Aggieguy said you need to figure out how your body reacts to test alone. Get bloods pre cycle and 8 weeks in. Focus on nutrition for adding lean bulk and workout like a beast here’s a solid read

https://www.eroids.com/forums/newbie-corner/steroids/how-to-run-a-first-...

If it’s your first cycle it should be testosterone only you dont even know how your body will react or if you will grow man boobs. Also you should be researching and looking at stuff before you even think about starting. Did you even do any blood work?