First check if the ghost even uses spirit box cause that might save you some time. The most important thing is keeping those room lights off though flashlights are fine. Make sure you're within about 3 meters when asking questions, maybe try right after seeing activity when you know the ghost is close. Some ghosts only talk when you're completely alone so double check the whiteboard and keep teammates away from doorways too. Always worth testing your mic in the options menu, switching to text mode can help figure out if its working right. Only certain questions get responses like "where are you" or "how old are you", so stick to those basics

If everything seems right and still no response, don't worry too much some ghosts just take their sweet time responding especially with basic equipment. Sometimes its just not meant to be and you should look for different evidence instead