Drop the magazine, make sure the chamber is empty.
Pull the slide back all the way and push the safety to 'on'; that locks the slide back.
Unscrew the barrel nut that's just ahead of the trigger guard; that allows the barrel to be removed.
Hold the slide back, push safety to 'off' and ease the slide forward and off the frame. Note: the recoil spring is under tension, if you release the slide it WILL shoot forward off the frame.
That field-strips is for normal cleaning. Use a good cleaning rod, jag, patches and bore cleaner to wipe out the bore. Some cleaners such as Eezox are also good for the other parts; use some on a soft cloth to wipe fouling off the slide face and anywhere else you find it, and clean the slide and frame rails. Before reassembly put a bit of good grease(I use Tetra) or a good oil on the frame rails.
Make sure the recoil spring is in place on the frame, put the slide back in place from the front and move it all the way to the rear. Place safety 'on' to lock it back.
Set the barrel screw into place and tighten the nut; make sure it's seated properly in the frame.
Pull slide back a bit, safety to 'off' and move slide into battery.
Disassembly beyond that point requires either a gunsmith, or finding the full disassembly instructions, some tools and some time.
Yes, they made that model
1974
1978
Best left to a gunsmith
1958
1941
Best left to a qualified gunsmith
25-125 USD or so
10-1000 USD depending on specifics
1949-1950.
SN does not have enough numbers.
High Standard 1959