Exporting multiple tracks at once

Hi all, hope you a doing fantastic. I’m a new user and I’d like to have some help.
I have several flac albums where the sound level is too low and I’m using Audacity to add some gain to these tracks. The main question is: is there a tool for adding the same gain to all files (single album) in a folder?

You can use the “Amplify” effect in a Macro (https://manual.audacityteam.org/man/macros.html)

How will you know how much amplification to apply?

Thanks for the reply. Simply I pre listen the tracks and decide how much gain apply by testing the level to avoid the clipping.

So I presume that ideally you would want some method to determine what the maximum peak level of the original flac files is, without having to test each one individually? Is that what you’re after?

Every album has its level. I try the new gain level on two or three songs of the album and hope to solve the low level volume.

Did this answer your question, or do you still need some help?

I’ll try this evening 'cause I’m still working