There's no way to reliably check the ATF level yourself on a 1998 Camry without this equipment. Attempting to check it incorrectly could lead to inaccurate readings or even damage.
If you suspect a problem with your transmission fluid, take your Camry to a qualified mechanic or Toyota dealership for a proper inspection and fluid level check. They'll have the correct tools and knowledge to determine if the fluid is low and address any underlying issues.