If you are used to react-with-an-emoji roles: this bot cannot see emoji reactions. It has no live gateway connection, and reactions only travel over one. Pickers here use buttons or a dropdown instead, which the bot does receive. Members press, get the role, press again, lose it. The emoji box in the builder just decorates the button or menu entry.
Handing out a role needs the bot to have Manage Roles, and its own role must sit above the roles it hands out. Drag it up under Server Settings → Roles in Discord. Roles the bot cannot reach are greyed out below.
Up to 25 roles per picker (Discord's ceiling for both styles). The emoji is plain unicode (paste one in); custom server emoji are not supported here.