Singer indicates that the 2430 to the Merritt 2404. The Merritt 2404 manual is available on the Singer support site: https://www.singer.com/support
. The current link to this manual is https://www.singer.com/sites/default/files/product_manual/9bb8bc029ac33374a16f6ef37fdb37c14c7a8356_0.pdf
. To wind the bobbin, make sure that the needle is up and lift the presser foot. Hold the hand wheel with one hand and keep it from moving. With the other hand, loosen the knob in the center of the hand wheel by turning the knob towards you. If the thread is not already on the spool pin, place it on the spool pin with the thread retaining slit to the right. Put the spool holder on the spool pin so that it holds the spool firmly.
Next snap the thread through the thread guide post and open the top cover. (If you have been sewing with the spool, unthread the upper thread back to the guide post.) Wrap the thread the bobbin tension disc going clockwise as you look at the top of the disc. (Bring the thread in front of the machine as you move to the left; then bring around to the back as you bring it to the bobbin winder.) Bring the thread up through the hole in the bobbin. Place the bobbin on the spindle with the hole up. Move the bobbin winder to the right. Hold onto the thread above the bobbin while you start winding the bobbin. After a few turns are on the bobbin, you can let go. After the bobbin is full (or full enough for your task), clip the thread and remove the bobbin. Move the bobbin winder to the left. Tighten the knob in the hand wheel by turning it away from you while holding the hand wheel.
I hope this helps.