An easy killer sudoku on this site never asks you for a 45-rule split or a locked pair. The hardest step is a single: the last cell of a cage, a cell with one candidate, or a digit with one home in a house. If a puzzle needs anything sharper, it is filed under medium or above, even if it looks small.
You will still see a few given digits, never more than six, and often none. They are there when a cage would otherwise have two harmless ways to be filled and a single placed digit makes the rest logical. They are not a substitute for the sums. The cages remain the clues.
Start by marking every two-cell cage that sums to 3, 4, 16, or 17, and every three-cell cage that sums to 6, 7, 23, or 24. That pass usually places nothing and removes a great deal. Then fill last cells. Then look for the digit that the notes have trapped in one cell of a box. The timer on an easy puzzle for a new player is often under fifteen minutes; for someone who has learned the combinations it is often under eight.
Mistakes are highlighted by default because a wrong digit inside a small cage is hard to see and expensive to unwind. You can turn that off in settings if you want the grid to stay neutral. Notes, undo, and pause are always there. Pause covers the board, so the screen can sit on a table without giving the puzzle away.
When easy stops teaching you anything, it is supposed to. Move to medium, where the new idea is a single application of the 45 rule or a pair. Staying on easy for a large streak is a fine way to learn the interface. It is a poor way to learn killer sudoku.
Related reading: how to play, the 45 rule, and the combination table.