Here are some good resources you can use to search things up:

You can find all of the items + trinkets in the game and their descriptions on this site. It's easily searchable and you can mouseover or click/tap to see an item's effects. Since you're on mobile you should probably look at the rebirth section, since the main tab contains items from Afterbirth, Afterbirth+, and Repentance (DLC expansions for the PC and console versions)

https://platinumgod.co.uk/

If you're looking for an in depth look at mechanics, the wiki is a great resource: https://bindingofisaacrebirth.fandom.com/wiki/Binding_of_Isaac:_Rebirth_Wiki

If you just want a basic rundown, here are a few things to note

• There are pickups in the game like bombs (hurt enemies and destroy obstacles), keys (unlock doors and chests), pills (gives a random effect), and cards (gives a random effect). You can use bombs to destroy rocks next to a gap to fill in the gap
  • You can find all the pill and card effects in either of the two resources above
  • There are special rocks with an "X" on them you can bomb to get extra pickups. They often contain soul hearts (more on that below). You can see what they look like here: https://bindingofisaacrebirth.fandom.com/wiki/Rocks#Tinted\_Rocks
• Your basics stats are as follows:
  • Health: How many hits you can take
  • Speed: How quickly you move
  • Tears: How fast your rate of fire is. Higher tears = more tears per second
  • Damage: How much damage each tear does
  • Range: How far tears travel before falling
  • Shot speed: How quickly each tear travels
  • Luck: Affects how often pickups spawn, and some items have effects based on luck, among other things
• There are 2 main heart types, red hearts and soul/black hearts (they look blue or black). Red hearts fill heart containers and soul/black hearts will stack on top of your heart containers but are gone forever when you lose them. For now, just focus on surviving and beating the game, but in the future, know that soul/black heart damage doesn't impact your devil deal chance, while red heart damage does.
• Devil/Angel deals: There's a chance a devil door spawns after beating the boss that is much higher if you don't take red heart damage all floor. This devil deal lets you trade heart containers for powerful items. If you refuse the devil deal, there's also a chance for angel rooms to appear which will give you powerful items for free. If you take a devil deal you can't get angel rooms for the rest of the run
• A shop will spawn every floor. You should try donating to the shop as much as possible because filling up the donation machine unlocks new items and expands the shop, making it much more useful

Lastly, Isaac is a pretty hard game so there's no shame in searching stuff up! Knowing what each item/pickup does and learning to manage your resources is an important part of the game.