i need help making a line art transparent. can someone please tell me step by step or give me a helpful website?

The simplest is to change the layer mode to multiply. This will make all whites transparent, all blacks black. You mal also have to adjust the levels first to get good contrast, or try one of the Auto options (all under the colour menu).

Then add a new white layer below your line art layer that you can then colourize/paint.

-Rob A>