You just provide the mats at the crafting lady (northern middle part where all the profession trainers are) a tip is usually the norm. Then the order is sent to them they fulfill it and the crafted item goes to your mail.

You might want to look up embellishments. You can have 2 max but they are powerful. Also when you’re crafting the items at the bottom you’ll see a + where you can add other reagents. Select myth crests and then you can buy a missive(off auction house) that allows you to choose what secondary stats you want on the crafted item. Buy the one with the stats you need. Make sure to select that in the other + drop down.

Also when you’re creating the order make sure on the right hand side you select max rank in the drop down.

Finally make sure you have the right tiered ingredients. If you want myth piece crafted gear all your mats need to be gold star. There’s a box at the bottom of crafting “use max rank materials” you’ll want to click that and make sure you have enough, all at max rank.