Best way to perform a leak down test on a 92 legacy   thanks

The same way you leakdown any other car? Pull all the spare plugs, then you need to find TDC of the compression stroke in cylinder 1. You can either use the method where you stick a finger over the plug hole to find TDC or pull the left timing cover cap. When the arrow on the cam gear points straight up you're at TDC of the compression stroke in #1. After that, every 180 degrees of rotation of the crankshaft you'll get to TDC of compression stroke of the next cylinder in the firing order, 1-3-2-4.