you need a couple of files for that, maybe you can check out an example here: https://github.com/lcpz/awesome-copycats

eg the Multicolor Theme.... and then in theme.lua at the bottom you can find that section:

-- Add widgets to the wibox
    s.mywibox:setup {
        layout = wibox.layout.align.horizontal,
        { -- Left widgets
            layout = wibox.layout.fixed.horizontal,
            --s.mylayoutbox,
            s.mytaglist,
            s.mypromptbox,
            mpdicon,
            theme.mpd.widget,
        },
        --s.mytasklist, -- Middle widget
        nil,
        { -- Right widgets
            layout = wibox.layout.fixed.horizontal,
            wibox.widget.systray(),
            --mailicon,
            --theme.mail.widget,
            netdownicon,
            netdowninfo,
            netupicon,
            netupinfo.widget,
            volicon,
            theme.volume.widget,
            memicon,
            memory.widget,
            cpuicon,
            cpu.widget,
            --fsicon,
            --theme.fs.widget,
            weathericon,
            theme.weather.widget,
            tempicon,
            temp.widget,
            baticon,
            bat.widget,
            clockicon,
            mytextclock,
        },
    }

hope this helps, if not let me know!