Bike is home question about givi top box

Well I trailered the bike home from the bike shop but I had to take it out for a spin. I didn't go far because we have a lot of sand and salt on the road so just took the bike around the crescent a few times.
I absolutely love it! I find that it is very light to handle, I have been use to the heavier motorcyles so having a light bike is very refreshing. It felt a bit strange with my legs bent wihout having a tank to hold but when I stretched my legs out and rode with one straight out and one bent I felt like I was on my old motorcyle with the highway pegs and it felt very natural. I can't wait for Spring to get out more.
I wasn't sure how the throttle would work without neutral but am so relieved to find out that you can take your hand off the brake and it won't move forward till you give it gas, that makes me much more comfortable knowing this and yes I will still use my brake for saftey reasons.
I purchased mine with a Givi box and I can't quite figure out how to get the latch on to lock it. I can open it no problem but can't seem to be able to lock it. Its a Givi either E350 or E340. The instructions say to have the latch hooked but I can't seem to be able to latch the hook, must be doing something wrong. Is there a trick to this or am I just too excited about the bike that I just can't focus on a lock. lol