Its actually a starter relay, but most still call it a starter solenoid
It has 2 larger posts, and one or 2 smaller posts, AND a metal frame that must have a good ground to inner fender, which must have a good ground to battery negative
The 2 larger posts are not specific there is no "reversing them" issue, BUT...............
They are wire "group" specific
One larger post will have the Battery Positive cable connected to it and a few other wires/fusible links with it, this is the MAIN 12volt distribution point for the whole vehicle
The other larger post can ONLY HAVE ONE CABLE, it runs to starter motor
As said, it doesn't matter which side is which, but it must be "group" wired this way
Smaller posts ARE labelled, "S" for START, and "I" for IGNITION
Only the "S" post is used after 1975 or so
"S" post will have just 1 wire, red/blue, it runs into the cab to ignition switch under steering column
When key is turned to START that red/blue wire gets 12volts and that activates the starter relay which activates the starter motor
This red/blue wire can have a Neutral Switch on it, so starter motor can not be activated unless clutch pedal is down OR Automatic is in PARK
You are not clear on what wire you had to remove, "starter wire" can mean smaller "S" post which should only have 1 wire, red/blue
Or the larger post starter motor wire, which also should only have the 1 cable to starter motor
The larger post with Battery Positive cable will also have Alternator wire, Engine bay fuse box wire, and Cab ignition switch wire, may have 1 or 2 more depending on Options