How do I obtain different tanks in World of Tanks on ps4

You would be needed to start the "grind" yes you read it correctly, the GRIND

so the tank you wanted to play as is the Jagdtiger, it is at tier 9. Means you would have to grind your way up to there, starting from the tier 1 tank, the leichttraktor at tier 1, pzJager at tier 2, Marder 2 at tier 3 and the list goes on. It would take you a while to get to the higher tiers, but it is worth it ;)

Your second question, "Can i use money to buy it", There are 3 different scenarios

1.) YES .... but there's a catch - world of tanks uses a system where you earn "combat xp" in your own tank as well as "free xp". Free xp is can be used to unlock modules across all types of tanks and tech trees (hence the word "free"). Once you have elited a tank, you will be earning Free XP instead of combat xp *note the golden star icon. With the xps earned from an elited tank, you can use Gold to convert them into free xps, and in turn spend it to progress your way to unlock your desired tank, but mind you, you will be needing A LOT of them.

2.) YES ..... but theres a slight difference -im not too sure about PS4 variant, but all the 3 franchises have premium shops. And at the premium shop, you have the chance to buy the Jagdtiger 88 with real money if you so desire. Basically its a Jagdtiger with the long 88 gun, with fast rate of fire but lower alpha damage as compared with its tier 9 variant. So there you have it, a Jagdtiger albeit with a smaller gun, but still, its a jagdtiger

3.) NO - since you say you have little to no experience in World of Tanks, i would say you wont have played enough games to gather enough xps in an elited tank to proceed with the plan as per bullet 1.) . So, play more ;)

Note: Turretless Tank Destroyers are somewhat powercreeped in this game, so starting the game with the Jagdtiger in mind would be somewhat troublesome, tiring and disappointing for you, but yea, the choice is up to you

one more thing, world of tanks requires dedication and lots of time investment, so it is not for the faint-hearted.

Fun Fact: Premium tanks bought in the premium shop or bought in the in game tech tree with gold will have the following benefits:

1. you earn more credits per battle
2. you earn more crew xp per battle
3. some premium tanks have premium matchmaking (it wont see tanks 2 tiers higher than it)
4. most premium tanks are comparably worse than the normal tanks at its tier, in terms of stats, but you will be having more credits and xp earned as a compensation :D

so there you have it ;)
if you're ever so inclined or interested in World of Tanks, you can check out the following youtube channels for reference, though they are on pc platform, but the gameplay and game mechanics are all the same.

Quickybaby's youtube channel https://www.youtube.com/user/QuickyBabyTV

Have fun on the battlefield, and hope you enjoy the game :)