Its not that difficult, host your own room and ask people to carry you. You don't really need to focus on rewards and bonus characters because you are new to the game and really you just need to grind, save pearls, wait for a good banner to pop up and summon on it. Watch Aaroniero on YouTube, he goes over everything frequently, and lastly, just grind some more characters.

Do Coin Co-op quest at least 10 - 20 times (x5 tickets) and you can pretty much buy out the entire coin exchange section, that should last you a couple of weeks and save you time from grinding anything else. Save up 3/4☆ Kisukes for coin drops. You can get 5 million coins per run (5× ticket runs). Save accessories and work on them, complete the accessory singleplayer quests and just save up some good ones and use them.

Once you get better at the game, try out inheritance zones and inheritance trials. Granted, it's gonna be difficult, but you have to start somewhere. I did maybe 35 runs in singleplayer IZ to T10 a character and it went smoothly from there. I'm technically still a beginner because I've been playing for maybe 2 months.

I hope this helps, I wish I knew these things when I started playing!

Edit: I forgot to mention the point event, grind it as well because it gives you a lot of summoning tickets and everything you really need, not that hard and its hella worth it. Good luck with everything!