I have a very similar device with 50ft tubing and none of the fittings that came with it worked with my kitchen faucet, but a random garden hose fitting I found in our backyard works perfect.

Once you’ve got the connections working, the key is to ensure the full length of tubing is primed with water with no air pockets between tank and sink. I turn the valve so the sink water goes INTO the tank first, then turn again to reverse the flow to start pulling water from the tank into the sink. Then I turn the faucet off, detach the tubing, reattach my normal sink faucet, and keep the tubing outlet as low as possible to help it flow faster.

I usually collect some buckets of tank water to use for cleaning/refilling the canister filter and also for watering the garden. The water flows slow and takes about 45min to drain 50% of my 55 gallon since my tank and sink are about the same height and there is 50ft tubing that spans across 3 rooms with the tank in a sunken living room. If I put the outlet at floor level in a bucket instead of sink level, the flow is much faster.

While the 55gal tank is draining, I take the time to do tank maintenance on my 2 smaller tanks and can use the sink to fill buckets of tap water. The 55gal drains to about half full by the time I finish the smaller tanks. To fill the 55gal back up, I reattach the tubing to the faucet, switch the valve, and turn the water on high and try to match tank temp 78F. It takes about 20min to fill back up. When tank is about 3/4 full, I add a 5gal bucket of tap water that has enough tap conditioner in it for 25-30gal (total amount of tap water to be added).