Top one, that would be the ignition relay, like turn the key, this closes and puts power to the small wire on the starter, not needed if you wire it right. Also note that you need to put a cranking 12v to the ECU, it will come off of this, or I can help you with the pin.
#2 Ignitor plug
#3 brown main power relay, green plug fuel pump
#4 crank sensor, cam sensor, knock sensor, O2 sensor, air flow sensor (make sure you get the aluminum tube for this because early ones like this were a 5 speed) Also make sure you have the flow sensor that matches your ECU, you will get a code saying wrong air flow sensor if you mess them up.
#5 Alternator junk, you can take the two white wires straight to the battery. Also do yourself a favor and step up to the impreza/late 90s outback alts. You ditch one wire from the plug and more or less make a one wire alt, not unless you want a dummy light. And those two big plugs go to your intake harness and carry everything other then the pre mentioned plugs.
I just had this long pictured post going.
I just don't know what this is.
I know these
Fuel and Main relays
coolant , knock, etc, and the intake air thingie..
then Alternator, and intake harness plugs
Thos ebig white wires come out off of that last pic...