For a low lvl player a lvl 1-45 is good enough to get you going but when you get the kibble a lvl 116-120/150 should be your main goal. High damage means more metal per hit & weight is your 2nd most useful stat to carry more. P.s taming a lvl 145 ankly now ;)
They are very slow and can't turn around very easily. So come up behind one and shoot it with tranq arrows. You should be able to knock it out before it turns around and attacks you. But don't get too close!! Watch out for other Ankylosaurus too. They are travel in herds
If you are taming an anky use a scorpion to ride and a cross bow as the scorpion allows u to shoot from on top and it is fast plus if u run out of arrows u can go in with the scorpion to finish the knock out.
Remember, when using the anky in a mining platform it has a wide range of attack. It doesn't have to be touching the rock to harvest it, only has to be in range. This will help prevent getting knocked off as often.
Once you have have a high level one, they make a great taming aid: you can fire tranq darts while riding this mount, and it'll tank all the damage. I once put out 6 member pack of raptors while riding this animal.same with the first Rex I tamed.