Hi Karen and welcome to the forum. Squeaks usually need oil. I prefer a light oil in a spray can like BreakFree. Here's a reference pic. for the following info::
Terminology:
1. Sprocket assembly
2. Spine
3. Idler pulley
4. Drum
Lube points:
A. Roller bearings and
sprocket shaft for sprocket assemblies
B.
Drum shaft and roller bearings (outside shown, but I prefer to lube the inside)
C.
Idler shaft and roller bearings
Circles:
Idler adjusting nut (bottom)
Front chain/cable nut (right)
Rear chain/cable nut (left)
Lubing tips -- I like to lube anything that moves, but pay particular attention to the roller bearings around the three shafts mentioned. After lubing, exercise the parts to spread the lube, then wipe off any excess.
Chain/cable adjustments -- If you pinch the cables together
firmly you should get some flexing I look for about 1/8" idler cable and front chain, and about 3/16 rear chain. Tighten in the order mentioned as one adjustment may affect another.
Notice there are adjustment nuts on both ends of the cables. If you just tighten one nut, you pull the fin to that side. Better to see if the fins are leaning, then adjust the appropriate side; if centered, tighten or loosen both sides equally.
for starters, you may have just over tightened the one chain. If so, loosen it and check the fin straightness.
This ought to get you back in operation without squeaks!