To change your own timezone, open Infraspeak web and click on your initials/profile picture at the top right corner to open your Account Details. Under "Preferences", you'll find the Timezone section. Click on it to select the desired timezone, and it will be saved automatically once you close the Account Details window.

If you have an Administrator profile, you can alter other users' timezone. To do so, open Infraspeak web and access Settings > Users. Select the user you wish to edit and click on the pencil icon to start editing. In the Timezone section, select the desired timezone. Finalize by clicking on "Save Changes" at the bottom right.