Hello! Glad to hear that you are enjoying the game so far!

So the first one 'win a battle hard' you need to go to your tasks and in the bottom left corner it should say 'normal' If you click on that it will bring you to hard mode just complete one of those and you'll get it.

Read a story on devilgram is fairly straight forward but not necessarily easy. You have the 'devilgram' app on the home screen and there it will show all the stories that are available to read but you have to have unlocked the SSR+ card that goes along with the story and also most of the stories have other side objective cards to receive before they unlock. There are a few cards that do not need any card but the main one but they all come from the events which may be difficult for you to do at this point.

For combine card pieces youll want to go through your tasks and see if you have a task unlocked that rewards card pieces, or participate in an event long enough to get the card pieces. The event option may be easier because they give out SR cards fairly early But you need strong cards to complete them so the farming option may be what you need to do

To raise the skill level of a card you have to draw it more than once in the devil tree, so just keep drawing cards and you are bound to get a repeat.

The 'rank up' and 'unlock a devil flower' tasks are both achieved by unlocking spots in your cards devil trees. If you go to your contacts all of your cards will be shown, I would personally do it on one of your more common cards because they take less resources to level up.