It's not you. Just because it's a supposed 'smart phone' doesn't necessarily mean it makes life materially easier, certainly not initially anyway. The learning curve will take awhile and even then you find yourself occasionally wondering if the technology is really improving your life or not. The bottom line is for many people these phones are simply entertainment devices that we justify by pontificating about how much more "productive" they make us.
I find using using google play store from the computer vs from the phone is easier for me, if for no other reason than I severely dislike poking out a one fingered input on the tiny screen of the phone. Or reading from the tiny screen vs the laptop/desktop.
There are likely multiple apps for whatever you want to do and google play provides user reviews that may or may not be helpful with the selection process. At the same time I sometimes feel overwhelmed by the number of reviews and info on an app and just download the darn thing and try it out. Then uninstall it and try another one if it doesn't work out.
The other thing I like about the google play store is it will tell me before I download the app if the app is not compatible with my phone (older phone).
I like apps that have a pc interface as well as the phone, as again I see no reason to sit there pecking out an entry on the phone screen if it can be done on the pc with an actual keyboard.
An app that I like and use is ourgroceries. This is a list app that allows for my wife and I to access/modify various lists (shopping, packing etc) from any device, phone, tablet, computer. It remains constantly updated. I keep the app open on my pc desktop as I frequently think of things to add/delete during the day. Further, I access it frequently from the phone to make notes while out and about. This is by far the most used app for my wife and I.
The most recent app I have tried and did not work-out is a business expense app to track mileage and business expenses. I have yet to find one that interfaces well with the pc and is not ridiculously over-complex or so buggy that it's near useless. I need to let some time pass and I calm down before trying anymore. Went to back to using paper expense books (gasp!).
One final note on important attributes of the phone itself. For me one of the should-be benefits of the smartphone is it should reduce the number of things I have to carry on a mostly daily basis. The camera on my old phone is very poor and not as good as my digital camera. I use a camera frequently - taking reference pictures of shop/repair projects etc. The camera on my sons newer phone is very good and this is perhaps the one thing I'm looking forward to when I someday purchase a new phone. Conversely, one of the things I'm not looking forward to on a new phone is they all seem to be the size of a kitchen table these days. I'm pretty set in my ways, and if the phone doesn't fit in the side-pocket of my carhartts like my current phone then we are going to have problems getting along, no matter how good the camera may be.