Your first opportunity for this will be at
minimum lvl 20 in the first city "Kyovashad" but can be done anywhere you have access to a Blacksmith and Jeweler.
It can be done at anytime after you can access them and the requirements don't need you to do them at the same time.
Visit the Blacksmith and speak to the NPC working on the anvil. Scroll to the third option on the left side of the screen above the smith's image, using
it'll say "upgrade item"
Select either a weapon or a piece of armour then hit the upgrade button at the bottom of the screen, provided you have the resouce mats for it. Most likely a dozen or so pieces of leather and a couple thousand gold.
Repeat this step for the other piece, be it armour or weapon depending on what you did first.
Next head over to the Jeweller, their icon is a gemstone.
Same deal here, pick a piece of jeweller to upgrade, have the required mats and then upgrade.
Achievement should pop right away