Since skystones are the most important currency of this game I will start by giving some tips on saving and acquiring skystones ! Login everyday , you can get 100 skystones every week . Complete daily and weekly reputation in Three sisters' Diary you can get 50 skystones every single day and after completing weekly missions you can get gold transmit stones too . Max out sanctuary especially Heart of Sanctuary as it gives skystones . Climb arena and Abyss as much as possible . You can get bulk amount of skystones from arena ! Progress in story chapters and side stories , they will provide you skystones and various rewards . Clearing ncp challenges in arena can give you skystones too . 

Now some tips about summons and Heroes ! Epic 7 is a beginner friendly game and you can acquire more than enough 5 Star heroes to help you clear chapter 1 ! You can get heroes by completing connection mission , hunt mission and by spending covenant bookmarks ,. mystic medals and galaxy bookmarks . Usually veteran players save their resources for a rate up banner as it guarantees the Hero after 120 summons ,it's a safer option than spending your bookmarks endlessly but if you're feeling lucky go ahead . Try collecting heroes who are versatile as it will help you to progress faster in both PVE and PVP . Go through each and every heroes skills carefully so that you can know there strengths and weekness !  Moonlight heroes are more preferable than normal heroes cause they help in long run . 

Battle tips ! A good team generally consists of 2 Dps ( main damage dealer) , soul weaver and tank . Bringing heroes who can apply buffs and debuffs (specially defence break ) makes the battle easier . Add friends so that you can use their support heroes for battle . 

Hunt tips ! Wyvern hunt is most popular hunt as it provides you speed and crit gear which are mainly used to climb arena . After a certain point of time you too will need to farm wyvern hunt for gears . A suggested team composition for wyvern hunt is a debuffer ( absolutely compulsory as the dragon will get extra turns if not debuffed ) , a soul weaver ( who can cleanse or apply immunity ) , 1 or 2 dps( main damage dealer ) . Personally I used Seaside Bellona , Angelic Montmorancy , sigret and luluca . But you can use other heroes who meets the same requirements but make sure all of them are water elements (increases the chances of winning )  . Good gears are a game changer . Depending on your strategy and team composition equip your heroes with gears . 

Extra tips -

Don't use molagora on heroes that you won't be using for long time ! They are very rare and expensive . Skill enhancing a hero makes them stronger. The same goes for phantasma and Penguins . As a newbie you might struggle to acquire these ,so spend them wisely . 

Which moonlight hero to have form moonlight connection ? 

basically I would suggest Arbiter Vildred or Specter Tenebria as they are easy to build and versatile . 

where to use gold transmit stones ? 4 -5 star Hero summon ticket or Galaxy bookmarks ? Both !  You can get a 5 Star hero from the ticket and 3 star from the bookmark or you could get a 4 star from ticket  and 5 Star from the bookmark it entirely depends on your luck  . Usually people prefer a moonlight Hero over other elements . 

If you are going to unequip your hero gear I suggest you to wait for unequip buff . It saves a lot of gold ! 

complete daily mission for more energy and rewards ! 

Joining a guild has many benefits  ! You can participate in guild battles and get mystic medals . You can buy good Artifacts and special elemental bookmarks ! 

Almost all units are decent and have good kit what matters is their gearing and composition ! Even some 4 star heroes are as good as 5 stars . Honarable mentions ( not Ml )Angelica , Achates ,  Rose , Cidd ,  Mercedes, Schuri . 

Complete speciality change quest , Adventurer Ras , Angelic Montmorancy , commander lorina , Researcher Carrot , Falconer Kluri  are a must ! 

Kiris and Taranor guard are Abyss Gods ! 

After you have progressed a lot in arena ( master rank ) you can try for limited heroes which will help you further . 

Carefully spend your resources.  Experiment with different gears and compositions !  And remember to enjoy the game and have patience . You can't progress this game in just one night so take your time . 

Thanks for reading !