I have those four holes and I need to somehow make a good connection with them and the Arduino. I'm using a jumper wire and I'm trying to solder it but the solder won't stick. I don't know what to do. Is it possible to do with household items (because coronavirus doesn't allow me to go out and shops are probably closed)? I don't have a solder paste.
Figure 1. Detail from OP's photo.
There is no sign of a soldering attempt on this joint.
- Apply the solder-wetted soldering iron tip to the PCB pad and the pin simultaneously for a couple of seconds to heat it up.
- Feed in a suitable guage solder with flux core until the joint and the pad are wetted.
- Withdraw the soldering iron and allow the joint to cool.