So sorry that your grandmother is not with you to see you using her machine.
The manual for the machine cannot possibly be outdated as it was written specifically for this model.
Instruction manuals will instruct you on how to thread a bobbin and the machine (thread the top thread with the presser foot up - always); how to change a needle and presser foot. The manual also indicates settings for stitching and there should be a section for maintenance.
Check the manual to see if you forgot to disengage the bobbin winding features or if the feed dogs have been disengaged.
If the fabric is feeding, but the threads are not forming stitches, then the needle is in wrong.
Rule of thumb is the long grove on the needle faces the direction of the last thread guide. If the last thread guide is on the front of the machine, the groove faces forward. The upper part of the needle shaft is flat is is opposite of the groove and in this case faces to the back of the machine.
If the last thread guide is on the left side of the machine, the groove faces to the left; flat side of the shaft faces right.
Also, check the bobbin case. Place the bobbin into the case so the thread feeds clockwise and through the guide on the side of the bobbin case. Hold onto the end of the thread so the bobbin case resembles a yo-yo. There should be a slight resistance to the thread as it feeds from the bobbin spool.
If the thread feeds to freely; tighten the screw on the bobbin case. Too much tension on the bobbin thread; loosen the screw. Right is tight and left is loose. Make teeny-tiny adjustments.