Ok so I've seen a lot of people having trouble with Jad. This guide is made to help you get firecape without any trouble (You don't need maxed stats or Expensive gear).
General Rule: Always Kill the 180s
first and the the 360s
last and keep Protection from Mage on at all times
except when fighting Jad (Wave 5)
This minigame is 100% safe. You won't lose any items if you die
Inventory/Equipment Gear
Note: I'm using the same inventory and equipment in the screenshots. I only put more superrestores and less food because I was making sure I wouldn't run out of prayer while taking screenshots. Note: The food and the super restores are more than enough and i ended up having more than half of my superrestores unused.
Use this equipment just as reference so for instance if you have a defender or d chain or whip then definitely swap those in ! However the equipment will still work pefectly.
If you don't have Barrows gloves you can use Dragon gloves or Black d hide vambraces instead.
Ok so to get to Tzhaar cave click on minigame teleport in your spell book then teleport to tzhaar cave
Before you enter the cave make sure you pot. You can also turn your prayers on so you're ready because monsters attack you the second you get in
We'll be using a lot of super restores so make sure you make use of that by keeping piety or chivarly (depending on your prayer level) on at all times. except when fighting Jad cause you'll be using range.
1st wave: 
First wave consists of 2 level 45s 1 level 90 1 lvl 180 and 1 lvl 360
In this wave start by killing the level 180 first (you can use dds special to finish him quick) Getting rid of him early is important as he can hit 200+s on you using melee attacks. your next target should be the level 90 as he can still deal significant damage on you using ranged attacks. Then the 45s then the 360.
2nd wave: 
Second wave consists of 2 level 90s , 1 level 180 and 1 level 360
Follow the general rule, eliminating the 180 first then the 2 90s then the helpless 360(who will be hitting 0's on you 100% of the time as you have protection from mage on)
3rd wave:
Third wave consists of 2 level 180s and 1 level 360
Again start my eliminating the 2 level 180s first then the helpless 360 . Be careful on this wave and pay close attention to your hp as the 2 level 180s can deal very high damage together and can easily kill you if you're not careful.
4rth wave
Fourth wave is the easiest of them all. You can finish it, taking absolutely no damage just by making sure your protection from mage prayer is on , infact always pay close attention to your prayer points as if your prayer goes down the level 360s can deal unimaginabely high damage and can down you in a blink.
5th and FINAL wave (Jad)
After you've killed the 2 level 360s and are done with the 4rth wave you have about 10 secs to prepare for the last and probably hardest wave. You Should prepare for Jad by refilling your hp and prayer points, potting range and defense and switching into your ranged gear and turning protection from range prayer on
As long as you are ranging jad He won't be able to melee you and will use only 2 types of attack
Mage Attack:
Jad appears to be moving backwards standing on his hind legs for a few seconds before shooting fire at you.
Turn on Protection from mage .
Ranged attack:
Jad stands on his hind legs and comes down, slamming the ground with his front legs.
Turn on Protection from range . You can also dodge the attack by moving away from the square but i prefer to do it this way.
Keep switching between protection from mage and protection from range depending on his attacks . Don't get into a certain rhythm while switching as jad has absolutely no pattern of attacks. Also don't switch too fast before you know what that attack is (don't be too slow either)
NOTE: Make sure you're watching your prayer. There's nothing more frustrating then running out of prayer while you're fighting Jad.
After about a minute of Switching prayers Jad will finally fall and the fire cape will be yours. You can get close to Jad to watch his Hp but I don't recommend it if you're just starting as the closer you are the harder it is to see his mage attack coming.
You may fail on the first or second try (but i guarantee you'll get it in no time)
I hope this helped
