How do I show error message?

how can i an error massage for some and it disappear

Please explain what type of error (from which component) you want to display
Show your relevant blocks, or screen where the error arises.

Hello Opk

In the Blocks Pallet, see the Blocks for the Screen. You will find one there for capturing error messages. Or you can download a (free) fully-defined one from my site - transfer it into any other projects via the Backpack.

What to show on the screen is that i have if else if code which is check if the fist condition is true it should show the error massage else if the first condition is false it should continue to run the code

Use a Notifier