Start with kahrun gear in HP for your support set (for mace and shield leave them last or don't bother too pricey, you can start with that shield you get at level 1 and any mace with cast speed), then the superior gear you can get for that spec is from rune shield tower/illuminary obelisk.
For your dps set try starting with blood mark gear you already need the accessories for everything pve and pvp in any spec to start with, and ofc socket in crit until you are capped then in attack, I assume you will have enough precision. Then you will need a good weapon, there's options depending on you. You can try farming and buying ancient coins for the weapon and put a BM wep under it is good starting weapon for DPS and will be your pvp weapon for a long time. Or if you get in groups in high level instances and get lucky on drops do w/e works for you, you should get in some instances easy as a support in kahrun gear and ofc your support stigmas.
And that's for pve to start with, for pvp you will need multiple gears sets obviously as a chanter, your second set after dps should be a block one, then a magic resist one if you want too. Just make sure to buy the proper parts for each set you are planning to do. Block set is the cleric one with mb (and you will need the shield too obviously but you don't need the mace for a support pvp set just any good pve mace), the chanter one has parry and you make it for dps.
As actually playing chanter you have multiples ways and stigma builds depending on you, as a full support you'll want the full support branch ofc and the other normal stigmas for that, your job is to have the correct mantras depending on your group and what you are doing, spamming your words to keep them up at all times and be wary of your mana, making sure everyone is buffed and also refresh it on the one that died, you job is also to rez people mainly not the cleric cause the cleric need to keep healing, if he starts rezing the other might die, he only rez group of people that are dead and then you protect him, generally you will need to heal the tank and the cleric as your focus. You will not be healing the whole group yourself thats the cleric job, you just support him in healing and you support your group in buffing their dps and defense. And ofc that doesn't mean never healing the other when in need, that depends on the situation.
Once you are confident enough and comfortable it's time to go even beyond in what chanter can do, keep in mind some instances still require you to be full support. Later when you'll get good pve gear that hp won't be an issue the most optimal way is to actually play as a DPS, you need to master weaving (having a good ping helps), finding the best rotation for you, as for stigmas in this way don't take the full DPS branch, that's for solo pvp. You'll want to be hybrid, doing dps as well as buffing your group dps, putting some heals here and there, rezing too. Like a normal scenario when on a boss you can do your rotation while finding some gaps where to insert a quick word of inspiration and also weaving it, putting the recovery spell on the tank etc... chanter is more fun this way instead of staying in place not moving pretending to be a cleric.
For selecting allies default keys are the F1-F6 keys while F1 being yourself, so either put other keys or arrange your party in the UI to be optimal and quick select allies you need to do stuff to. For scrolls/food macros can work but not reliable, you'll need a buff pet. I use Macros to switch gear. Sometimes even in like dps gear and things go to the shitter and you need to support, switching to your heal set (mace with cast speed) gonna help, also a quick tip is to right click remove your rage spell when you switch to healing cause it reduces your casting speed, putting a cast speed scroll too on top is nice.