I'm trying to figure out a way of drawing so i can color without fully lining my art. When i use the selection brush in paint tool sai, it'll seem like my selection is a line and will complete a drawing, ex- completing a circle, and when i use the fill tool it will fill everything except the circle
https://cdn.discordapp.com/attachments/ ... nknown.png

however, with krita, it takes it as it's primary selection, filling everything except what was selected https://cdn.discordapp.com/attachments/ ... nknown.png

how can i get it to work how paint tool sai does it? I know i have on a local selection mask, but even with it off it works the same

To get back to your first statement: read https://docs.krita.org/en/tutorials/flat-coloring.html . I don't know painttool sai, so the rest of your post doesn't really make sense to me.

You most probably wants either removing parts of the selection (deselecting only a part of the image) (select any selection tool and check Tool Options - there is an option to Replace, Intersect, Add, Subtract, and Symmetric Difference - you want "Subtract") or inverting selection - go to Select -> Invert selection, then parts that were selected will be not selected anymore and parts that weren't selected will be selected.

Also useful tip - on the left corner of the bottom bar there is a small button that switches the view mode of the selection from ants (the outline) to "mask" (everything that is not selected is red) and the other way around.

If you need something else, please describe it more, for example by showing screenshots of what do you have now and what would you like to achieve.

The link to the manual, given by Boudewijn above, is a very useful overview and more detail is provided on individual tools and their uses throughout the rest of the manual which is very well written.

If you have non-closed lineart, one simple method for colouring is to add a layer above the lineart and draw 'closure' lines about two pixels wide to close your lineart and define the boundaries of the coloured areas. Then, with a colouring layer underneath these two layers, you can use the Fill tool with all check boxes empty in the Tool Options docker and a Grow Selection setting of 2 pixels to apply colour fills.
(This assumes you have your lineart on a transparent background. If not, you can convert it using the Colour to Alpha filter.)

The Fill tool has many options that you can explore and experiment with. The Selection tools also have many options (as indicated by Tymond above) which can be confusing at first. In your linked image, you seem to have selected everything except the region you wanted to fill. This depends on which options were active when you made the selection. Again, you need to explore and experiment with them.