Jack, you can waste years trying to learn drum tuning without instruction. Seek out a professional percussionist, holding an associate degree or better, who also plays the drum kit.
Mog's advice, "...tap on the head next to each lug ... Each lug should have exactly the same pitch" is correct, and essential to drum tuning.
To make the task considerably easier, use a simple accessory — a cloth damper disc 1/4 inch (6mm) thick and 1/2 inch (13mm) diameter, with a 5 ounce (150g) weight (figures are approximate) — placed at the exact center of the head. This causes the drum to sound an octave higher, and eliminates many overtones that obscure the pitch.
Rest the drum on a cushion to prevent the opposite head vibrating.
Adjust the internal damper (if present) to disable it. Completely loosen all lugs on the top (batter) head. To do this, always turn one lug and then the opposite lug 1/2 turn. Assuming the drum has eight lugs, numbered clockwise 1 to 8, they are loosened (or tightened) in the order
[1 5] [3 7] [2 6] [4 8]
Once loose, very lightly snug down each lug, so that it's contacting the hoop without applying tension. Without the cloth disc, tighten each lug 1/2 turn at a time in the order given above, until the average pitch is near A above middle C (lower for an unusually heavy head). Check pitches by tapping lightly about 1 to 1.5 inches (2.5cm to 4cm) from each lug. They won't be identical; you're looking for the most common pitch.
Put the weighted damper at center, and recheck pitch at each lug. When above average, loosen the lug and the one opposite 1/16 turn or less; when below average, loosen the pair of lugs. You should be able to dial in the pitch fairly quickly.
The bottom head (resonant or snare-side) is tuned by an identical process, except that the snares must be loose and held off the head. The head must be pitched higher, to about D or E above the A of the batter.
Excessive overtones (ringing) may be due to the batter being pitched too high, so slightly detensioning the head should be tried first. If there's some but not enough improvement, use small adhesive dampers applied 1/2 inch to 1 inch (13mm to 25mm) from the rim, distributed evenly. If you can't get overtones under control, consult with the percussionist or an experienced drummer.