Welcome! Usually you have to find an exercise similar to the one you are doing... so in this case weight lifting:moderate, would probably work.
The Activities section is so much more subjective than the Foods section that it is hard to really measure exactly how many calories an individual is burning. But with some experience and practice, you will figure out what works for you.
One word of caution: It is best to underestimate your calories burned and be happily surpised with accelerated weight loss, than to over estimate and be left wondering what you are doing wrong.
Now, get going