For setting the coordinates you can use the Hudmessage Generator in AMXX Studio. (values are: 0.0 to 1.0, -1.0 is centered; starting from top-left of the screen)
effects parameter specifies the hud message effect - 0 is fade in/out, 1 is blinking, 2 is effect of "writing" the message letter by letter
fxtime parameter is for the time/speed of those efects
holdtime is the time before the hudmessage disappears (in seconds)
channel specifies the hudmessage channel (values are: 1 to 4, -1 is auto) - this parameter specifies in which HUD channel the message will appear. There are 4 channels, that means there can be maximum 4 messages at the same time on the screen. If the specified channel is used by another hudmessage, then it will be removed to free space for that message. So it's better to use -1 to auto detect the free channel or use HudSync natives that will work perfectly without concern about HUD channels - it will detect them automatic and will prevent them from hiding from another HUD messages.