Hi,

first and not ment to be ironic - by studying the flight manual  :)

second, by looking into this forum, as this theme has been explained quite often before  :)

Apart from that and as a quick resolve, you bring power to your plane and then look up at the overhead panel. In the left (or first) vertical row, there on the upper left corner you can see a subpanel with three round irs setup switches, a few status lights , a numpad and a few other items.

Now, look at those irs setup switches - they have a few named positions. After "off" comes "align". Now bring all three of them into the "align" position and you will see them status lights start flashing. OK, wait for a while and they will go out. If so, set the status switch to "NAV".

Well done, buddy, you have just done your first IRS alignment  :)

Regards,
Werner