There is a Synthesizer based at theAcademy in Jinzhou.
In this menu, crafting is divided into three sub-categories.
It’ll also tell you what the item will provide for you.

Just in case it disappears.
The Refresh Time is stated underneath the items in the Menu.
Again, like cooking, you could raise your Proficiency in using the Synthesizer.

The more you Synthesize, the more points you collect to level up and unlock rewards.
This will also tell you how much more Proficiency you should probably make it to the next level.
That’s everything you gotta know about using the Synthesizer in Wuthering Waves.

As with any RPG, you’ll need to focus on exploring and gathering materials to utilize the Synthesizer.